# MPEP § 803.02: Election of Species Requirements – Markush Claims > Federal · Agency guidance · In force URL: https://www.frixlaw.com/law-library/statutes/MPEP_S803.02 ## Section - **Citation:** MPEP § 803.02 - **Heading:** Election of Species Requirements – Markush Claims - **Jurisdiction:** Federal - **Kind:** Agency guidance - **Status:** In force - **Text as of:** August 14, 2026 - **Source:** Compiled text - **Location:** USPTO MPEP / Chapter 0800 - Restriction in Applications Filed Under 35 U.S.C. 111 › Double Patenting / MPEP § 803.02 ## Text I. MARKUSH CLAIMS A “Markush” claim recites a list of alternatively useable members. In re Harnisch, 631 F.2d 716, 719-20, 206 USPQ 300, 303 (CCPA 1980); Ex parte Markush, 1925 Dec. Comm'r Pat. 126, 127 (1924). The listing of specified alternatives within a Markush claim is referred to as a Markush group or a Markush grouping. Abbott Labs v. Baxter Pharmaceutical Products, Inc., 334 F.3d 1274, 1280-81, 67 USPQ2d 1191, 1196 (Fed. Cir. 2003)(citing to several sources that describe Markush groups). When examining a Markush claim, the examiner may generally choose to require a provisional election of species from among patentably indistinct species or patentably indistinct groups of species. See subsection III, below. The applicant’s election serves as a starting point for the search and examination of the claim. See MPEP § 2117 for a general discussion of Markush claims, guidance and examples regarding the determination of whether a Markush grouping is proper, and rejections on the basis that a claim contains an improper Markush grouping. A rejection based on an improper Markush grouping should be made in an Office action on the merits. In certain circumstances, both a provisional election of species requirement and an improper Markush grouping rejection may apply to the same claim. See MPEP § 2111.03 , subsection II, and MPEP § 2173.05(h) for a discussion of Markush claims and compliance with the definiteness requirement of 35 U.S.C. 112(b) . II. PROPER MARKUSH GROUPING Pursuant to the Supplementary Examination Guidelines for Determining Compliance with 35 U.S.C. 112 and for Treatment of Related Issues in Patent Applications ( “Supplementary Guidelines” ), 76 Fed. Reg. 7162 (February 9, 2011), a Markush grouping is proper if: (1) the members of the Markush group share a “single structural similarity,” and (2) the members share a common use. Id. (citing In re Harnisch, 631 F.2d 716, 721-22, 206 USPQ 300, 305 (CCPA 1980)) etermining Compliance with 35 U.S.C. 112 and for Treatment of Related Issues in Patent Applications ( “Supplementary Guidelines” ), 76 Fed. Reg. 7162 (February 9, 2011), a Markush grouping is proper if: (1) the members of the Markush group share a “single structural similarity,” and (2) the members share a common use. Id. (citing In re Harnisch, 631 F.2d 716, 721-22, 206 USPQ 300, 305 (CCPA 1980)). Where a Markush grouping describes part of a combination or process, the members following “selected from the group consisting of” (or a similar introductory phrase) must be substitutable, one for the other, with the expectation that the same intended result would be achieved. Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp., 831 F.3d 1350, 1357, 119 USPQ2d 1773, 1779 (Fed. Cir. 2016)(“It is generally understood that … the members of the Markush group … are alternatively usable for the purposes of the invention … .”)(citations omitted). Where a Markush grouping describes part of a chemical compound, regardless of whether the claim is limited to a compound per se or the compound is recited as part of a combination or process, the members following “selected from the group consisting of” (or similar introductory phrase) need not share a community of properties themselves; the propriety of the grouping is determined by a consideration of the compound as a whole. See Harnisch, 631 F.2d at 722, 206 USPQ at 305 (“in determining the propriety of a Markush grouping the compounds must be considered as wholes and not broken down into elements or other components”). See MPEP § 2117 for guidance and examples regarding the determination of whether a Markush grouping is proper. In accordance with the principles of compact prosecution, if the examiner determines that one or more claims appear to include an improper Markush grouping (see MPEP § 2117 ), the examiner should require the applicant to elect a species not broken down into elements or other components”). See MPEP § 2117 for guidance and examples regarding the determination of whether a Markush grouping is proper. In accordance with the principles of compact prosecution, if the examiner determines that one or more claims appear to include an improper Markush grouping (see MPEP § 2117 ), the examiner should require the applicant to elect a species. Note that if a written provisional election of species requirement must be made separate from the first Office action on the merits, it should not include a rejection on the basis of an improper Markush grouping. Any appropriate improper Markush grouping rejection should be made in an Office action on the merits. III. ELECTION OF SPECIES PRACTICE FOR MARKUSH CLAIMS A. Overview Markush claims recite a plurality of alternatively usable substances or members. In most cases, a recitation by enumeration is used because there is no appropriate or true generic language. A Markush claim may include independent and distinct inventions. This is true where two or more of the members are so unrelated and diverse that a prior art reference anticipating the claim with respect to one of the members would not render the claim obvious under 35 U.S.C. 103 with respect to the other member(s). In applications containing a Markush claim that encompasses at least two independent or distinct inventions, the examiner may require a provisional election of a single species (or grouping of patentably indistinct species) prior to examination on the merits, with one exception. If the members of a proper Markush group are sufficiently few in number or so closely related that a search and examination of the entire claim can be made without serious burden, the examiner must examine all the members of the Markush group in the claim on the merits, even though they may be directed to independent and distinct inventions. In such a case, the examiner will not require provisional election of a single species kush group are sufficiently few in number or so closely related that a search and examination of the entire claim can be made without serious burden, the examiner must examine all the members of the Markush group in the claim on the merits, even though they may be directed to independent and distinct inventions. In such a case, the examiner will not require provisional election of a single species. See MPEP § 808.02 An election of species requirement is a type of restriction requirement. An examiner should set forth a requirement for election of a single disclosed species (or a grouping of patentably indistinct species) in a Markush claim using form paragraph 8.01 when claims limited to species are present or using form paragraph 8.02 when no species claims are present. See MPEP § 808.01(a) and § 809.02(a) . If a Markush claim depends from or otherwise requires all the limitations of another generic or linking claim, see MPEP § 809 . Following election, the Markush claim will be examined fully with respect to the elected species and further to the extent necessary to determine patentability. Note that where a claim reads on multiple species, only one species needs to be taught or suggested by the prior art in order for the claim to be anticipated or rendered obvious. See, e.g., Fresenius USA, Inc. v. Baxter Int’l, Inc., 582 F.3d 1288, 1298, 92 USPQ2d 1163, 1171 (Fed. Cir. 2009)(the entire element is disclosed by the prior art if one alternative in the Markush group is in the prior art). If the Markush claim is not allowable, the provisional election will be given effect and examination will be limited to the Markush claim and claims to the elected species, with claims drawn to species patentably distinct from the elected species held withdrawn from further consideration (the entire element is disclosed by the prior art if one alternative in the Markush group is in the prior art). If the Markush claim is not allowable, the provisional election will be given effect and examination will be limited to the Markush claim and claims to the elected species, with claims drawn to species patentably distinct from the elected species held withdrawn from further consideration. As an example, in the case of an application with a Markush claim drawn to the compound X-R, wherein R is a radical selected from the group consisting of A, B, C, D, and E, the examiner may require a provisional election of a single species, XA, XB, XC, XD, or XE. The Markush claim would then be examined fully with respect to the elected species and any species considered to be clearly unpatentable over the elected species. If on examination the elected species is found to be anticipated or rendered obvious by prior art, the Markush claim and claims to the elected species will be rejected, and claims to the nonelected species will be held withdrawn from further consideration. If the examiner determines that the elected species is allowable over the prior art, the examination of the Markush claim will be extended. If prior art is then found that anticipates or renders obvious the Markush claim with respect to a nonelected species, the Markush claim shall be rejected; claims to the nonelected species would still be held withdrawn from further consideration. The prior art search will not be extended unnecessarily to cover all nonelected species, and need not be extended beyond a proper Markush grouping. See subsection III.C.2, below, for additional guidance. Should applicant, in response to a rejection of a Markush claim, overcome the rejection by amending the Markush claim to exclude the species anticipated or rendered obvious by the prior art, the amended Markush claim will be examined again. The examination will be extended to the extent necessary to determine patentability of the Markush claim ee subsection III.C.2, below, for additional guidance. Should applicant, in response to a rejection of a Markush claim, overcome the rejection by amending the Markush claim to exclude the species anticipated or rendered obvious by the prior art, the amended Markush claim will be examined again. The examination will be extended to the extent necessary to determine patentability of the Markush claim. In the event prior art is found during this examination that anticipates or renders obvious the amended Markush claim, the claim will be rejected and the action can be made final unless the examiner introduces a new ground of rejection that is neither necessitated by applicant’s amendment of the claims nor based on information submitted in an information disclosure statement filed during the period set forth in 37 CFR 1.97(c) with the fee set forth in 37 CFR 1.17(p) . See MPEP § 706.07(a) . Amendments submitted after the final rejection further restricting the scope of the claim may be denied entry if they do not comply with the requirements of 37 CFR 1.116 . See MPEP § 714.13 . B. Provisional Election of Species If a claim that includes a Markush grouping reads on two or more patentably distinct inventions, a provisional election of species requirement may be made at the examiner’s discretion. When making such a requirement, the examiner will require the applicant to elect a species or group of patentably indistinct species for initial search and examination. The examiner should not require provisional election between species that are not patentably distinct, or when the Markush group is proper and there would be no serious burden if the species were searched and examined together. The examiner should not invite the applicant to elect any group of species that would clearly be rejectable either as an improper Markush grouping or under 35 U.S.C. 112(a) if presented in a separate claim rovisional election between species that are not patentably distinct, or when the Markush group is proper and there would be no serious burden if the species were searched and examined together. The examiner should not invite the applicant to elect any group of species that would clearly be rejectable either as an improper Markush grouping or under 35 U.S.C. 112(a) if presented in a separate claim. In accordance with current practice, when an examiner chooses to require a provisional election of species, in most cases the examiner should call the applicant to request a telephonic election. See MPEP § 812.01 . If the applicant elects by telephone, form paragraph 8.23 should be used in the next Office action on the merits. The examiner should note whether the election was made with or without traverse. If a rejection on the basis of an improper Markush grouping is to be made, it should be done in the first Office action on the merits with the written provisional election of species requirement. If a written provisional election of species requirement is made prior to the first Office action on the merits, it should not include a rejection on the basis of an improper Markush grouping. Any appropriate improper Markush grouping rejection should be made in an Office action on the merits. If during prosecution a new claim is added that includes an improper Markush grouping, or an existing claim is amended to include an improper Markush grouping, the examiner may require provisional election of species at that time, in the same action as any appropriate rejections . Include form paragraph 8.23.01 if the applicant declined to elect by telephone. C. Initial Examination of Elected Species 1. Rejection of Claims to Elected Species Examination on the merits begins after the applicant’s election s amended to include an improper Markush grouping, the examiner may require provisional election of species at that time, in the same action as any appropriate rejections . Include form paragraph 8.23.01 if the applicant declined to elect by telephone. C. Initial Examination of Elected Species 1. Rejection of Claims to Elected Species Examination on the merits begins after the applicant’s election. If the elected species or group of patentably indistinct species is anticipated by or obvious over the prior art, an appropriate art-based rejection of any claim that reads on the elected species or group of patentably indistinct species should be made. Non-prior art rejections that apply to the elected species or group of patentably indistinct species should also be made. If the election was made with traverse, it should be treated in accordance with MPEP § 821.01 . If the Markush grouping was improper, a rejection on the basis of there being an improper Markush grouping should be made as described in MPEP § 2117 . The examiner should use form paragraph 8.40 to make the improper Markush grouping rejection and to advise the applicant of the species that do not belong to a proper Markush grouping that includes the elected species. The form paragraph also serves to advise the applicant that a rejection on the basis of there being an improper Markush grouping is an appealable rather than a petitionable matter. Example 1. A claim is drawn to a proper Markush grouping of species A, B, or C. The three species are patentably distinct, and the examiner requires a provisional election. Species A is elected. The examiner rejects species A over prior art, and indicates that species B and C have not been searched and examined. Use form paragraph 8.01 or 8.02 as appropriate to set forth the election requirement. Example 2. A claim is drawn to a Markush grouping of species A, B, C, D, or E. The five species are patentably distinct, and the examiner requires a provisional election on. Species A is elected. The examiner rejects species A over prior art, and indicates that species B and C have not been searched and examined. Use form paragraph 8.01 or 8.02 as appropriate to set forth the election requirement. Example 2. A claim is drawn to a Markush grouping of species A, B, C, D, or E. The five species are patentably distinct, and the examiner requires a provisional election. The grouping of species A, B, or C is a proper Markush grouping. However, the grouping of species A, B, C, D, or E is not a proper Markush grouping. Species A is elected. The examiner rejects species A over prior art, and indicates that species B, C, D, and E have not been searched and examined. Use form paragraph 8.01 or 8.02 as appropriate to set forth the election requirement. The examiner should also reject the claim on the basis of there being an improper Markush grouping using form paragraph 8.40 . The improper Markush grouping rejection should indicate that species D and E do not belong to the proper Markush grouping of species A, B, or C. 2. Elected Species in Proper Markush Grouping Allowable over the Prior Art If the elected species or group of patentably indistinct species is not anticipated by or obvious over the prior art, the examiner should extend the search and examination to a non-elected species or group of species that falls within the scope of a proper Markush grouping that includes the elected species. The search and examination should be continued until either (1) prior art is found that anticipates or renders obvious a species that falls within the scope of a proper Markush grouping that includes the elected species, or (2) it is determined that no prior art rejection of any species that falls within the scope of a proper Markush grouping that includes the elected species can be made. The examiner need not extend the search beyond a proper Markush grouping prior art is found that anticipates or renders obvious a species that falls within the scope of a proper Markush grouping that includes the elected species, or (2) it is determined that no prior art rejection of any species that falls within the scope of a proper Markush grouping that includes the elected species can be made. The examiner need not extend the search beyond a proper Markush grouping. In other words, the examiner need not extend the search to any additional species that do not share a single structural similarity and a common use with the elected species (i.e., do not belong to the same recognized physical or chemical class or to the same art-recognized class and/or do not have a common use and/or do not share a substantial structural feature of a chemical compound and a use that flows from the substantial structural feature). The examiner should continue examination of the Markush claim to determine whether it meets all other requirements of patentability (e.g., 35 U.S.C. 101 and 112 , nonstatutory double patenting, and proper Markush grouping). In the interest of compact prosecution, the examiner should ensure that the record is clear as to which species have been searched and have been found allowable over the prior art. The examiner should indicate that the provisional election of species requirement has been modified if additional species beyond the elected species have been searched and determined to be allowable over the prior art. The examiner should indicate that the provisional election of species requirement has been withdrawn if the full scope of the Markush grouping has been searched and been determined to be allowable over the prior art. Note that the examiner can only make or maintain any restriction requirement if there would be serious search and/or examination burden. Clarity of the record with regard to the provisional election of species requirement is critical to proper application of 35 U.S.C. 121 in later divisional applications the Markush grouping has been searched and been determined to be allowable over the prior art. Note that the examiner can only make or maintain any restriction requirement if there would be serious search and/or examination burden. Clarity of the record with regard to the provisional election of species requirement is critical to proper application of 35 U.S.C. 121 in later divisional applications. If a Markush grouping as set forth in a claim is proper and election of species has been required, the examiner must continue to search the species of the claim unless the claim has been found to be unpatentable over prior art. An examiner may not (such as by way of an Ex parte Quayle action or a Notice of Non-Responsive Amendment) seek to require an applicant to limit the scope of a claim that is directed to a proper Markush group to a subset of species that falls within the scope of the claim in the absence of a rejection of the claim for not complying with the requirements for patentability (e.g., 35 U.S.C. 101 , 102 , 103 , and 112 , and nonstatutory double patenting). D. Final Rejection; Finality of Election Requirement An Office action may be made final if the requirements of MPEP §§ 706.07 - 706.07(b) are met. If a claim in a first application recites a proper Markush grouping that encompasses patentably distinct inventions, an examiner who has required a provisional election of species need not continue to search the claim if the claim is rejected over prior art in a proper final rejection. That is, in this circumstance, the applicant’s election loses its provisional status and is given full effect under 35 U.S.C. 121 . Furthermore, if an applicant files a second application that is a divisional application claiming benefit under 35 U.S.C. 120 of the first application, the 35 U.S.C. 121 shield may be applicable laim if the claim is rejected over prior art in a proper final rejection. That is, in this circumstance, the applicant’s election loses its provisional status and is given full effect under 35 U.S.C. 121 . Furthermore, if an applicant files a second application that is a divisional application claiming benefit under 35 U.S.C. 120 of the first application, the 35 U.S.C. 121 shield may be applicable. So long as the consonance requirement is met, a claim in the divisional application to a previously non-elected and unexamined embodiment may not be rejected on the ground of non-statutory double patenting over an embodiment examined in the first application. An amendment canceling the rejected species received after final under 37 CFR 1.116 may typically be denied entry on the basis that it would require further consideration and/or search. If the applicant’s provisional election was made with traverse and the requirement has been made final, the applicant may file a petition for review under 37 CFR 1.144 . See MPEP §§ 818.01(c) and 818.01(d) . Note that no Markush claim can be allowed until any improper Markush grouping rejection has been overcome or withdrawn (see MPEP § 2117 , subsection III), and all other conditions of patentability have been satisfied. ## Nearby sections - [MPEP § 801 Introduction](https://www.frixlaw.com/law-library/statutes/MPEP_S801.md) - [MPEP § 802 Basis for Restriction Practice in Statute and Rules](https://www.frixlaw.com/law-library/statutes/MPEP_S802.md) - [MPEP § 802.01 Meaning of “Independent” and “Distinct”](https://www.frixlaw.com/law-library/statutes/MPEP_S802.01.md) - [MPEP § 802.02 Definition of Restriction](https://www.frixlaw.com/law-library/statutes/MPEP_S802.02.md) - [MPEP § 803 Restriction — When Proper](https://www.frixlaw.com/law-library/statutes/MPEP_S803.md) - [MPEP § 803.01 Review by Examiner with at Least Partial Signatory Authority](https://www.frixlaw.com/law-library/statutes/MPEP_S803.01.md) - [MPEP § 803.02 Election of Species Requirements – Markush Claims](https://www.frixlaw.com/law-library/statutes/MPEP_S803.02.md) - [MPEP § 803.03 Transitional Applications](https://www.frixlaw.com/law-library/statutes/MPEP_S803.03.md) - [MPEP § 803.03(a) Transitional Application — Linking Claim Allowable](https://www.frixlaw.com/law-library/statutes/MPEP_S803.03(a).md) - [MPEP § 803.03(b) Transitional Application — Generic Claim Allowable](https://www.frixlaw.com/law-library/statutes/MPEP_S803.03(b).md) - [MPEP § 803.04 Nucleotide Sequences](https://www.frixlaw.com/law-library/statutes/MPEP_S803.04.md) - [MPEP § 803.05 Reissue Application Practice](https://www.frixlaw.com/law-library/statutes/MPEP_S803.05.md) - [MPEP § 804 Definition of Double Patenting](https://www.frixlaw.com/law-library/statutes/MPEP_S804.md) - [MPEP § 804.01 Prohibition of Nonstatutory Double Patenting Rejections Under 35 U.S.C. 121](https://www.frixlaw.com/law-library/statutes/MPEP_S804.01.md) --- Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S803.02. Check the current official text before relying on it. Not legal advice.