# MPEP § 2138: Pre-AIA 35 U.S.C. 102(g)

> Federal · Agency guidance · In force

URL: https://www.frixlaw.com/law-library/statutes/MPEP_S2138

## Section

- **Citation:** MPEP § 2138
- **Heading:** Pre-AIA 35 U.S.C. 102(g)
- **Jurisdiction:** Federal
- **Kind:** Agency guidance
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** USPTO MPEP / Chapter 2100 - Patentability / MPEP § 2138

## Text

[Editor Note: This MPEP section
has limited applicability
to
applications subject to examination under the first inventor to file (FITF) provisions
of the AIA as set forth in
35 U.S.C. 100 (note)
. Patents and
applications that contain (or contained at any time) at least one claim with a pre-AIA
effective filing date (before March 16, 2013) and at least one claim with a post-AIA
effective filing date (on or after March 16, 2013) are subject to the patentability
requirements in
AIA 35 U.S.C. 102
-
103
and
subject to
pre-AIA 35
U.S.C. 102(g)
.See
MPEP §
2159
et seq.]
Pre-AIA 35 U.S.C. 102
Conditions for patentability; novelty and loss of right to patent.
A person shall be entitled to a patent unless -
*****
(g) (1) during the course of an interference conducted under
section
135
or
section 291
, another inventor
involved therein establishes, to the extent permitted in
section 104
,
that before such person’s invention thereof the invention was made by such other
inventor and not abandoned, suppressed, or concealed, or (2) before such person’s
invention thereof, the invention was made in this country by another inventor who
had not abandoned, suppressed, or concealed it. In determining priority of
invention under this subsection, there shall be considered not only the respective
dates of conception and reduction to practice of the invention, but also the
reasonable diligence of one who was first to conceive and last to reduce to
practice, from a time prior to conception by the other.
Pre-AIA 35 U.S.C.
102(g)
bars the issuance of a patent where another made the invention
in the United States before the inventor and had not abandoned, suppressed, or concealed
it. This section of
pre-AIA 35 U.S.C. 102
forms a basis for interference practice. See
MPEP Chapter
2300
for more information on interference procedure. See below
and
MPEP §§
2138.01
-
2138.06
for more information on the
requirements of
pre-AIA
35 U.S.C. 102(g)
.
Pre-AIA 35 U.S.C
ere another made the invention
in the United States before the inventor and had not abandoned, suppressed, or concealed
it. This section of
pre-AIA 35 U.S.C. 102
forms a basis for interference practice. See
MPEP Chapter
2300
for more information on interference procedure. See below
and
MPEP §§
2138.01
-
2138.06
for more information on the
requirements of
pre-AIA
35 U.S.C. 102(g)
.
Pre-AIA 35 U.S.C.
102(g)
issues such as conception, reduction to practice and
diligence, while more commonly applied to interference matters, also arise in other
contexts.
Pre-AIA 35 U.S.C.
102(g)
may form the basis for an
ex parte
rejection if: (1) the subject matter at issue has been actually reduced to
practice by another before the inventor’s invention; and (2) there has been no abandonment,
suppression or concealment. See, e.g.,
Amgen, Inc. v. Chugai Pharmaceutical
Co.,
927 F.2d 1200, 1205, 18 USPQ2d 1016, 1020 (Fed. Cir. 1991);
New
Idea Farm Equipment Corp. v. Sperry Corp.,
916 F.2d 1561, 1566, 16 USPQ2d
1424, 1428 (Fed. Cir. 1990);
E.I. DuPont de Nemours & Co. v. Phillips
Petroleum Co.,
849 F.2d 1430, 1434, 7 USPQ2d 1129, 1132 (Fed. Cir. 1988);
Kimberly-Clark v. Johnson & Johnson,
745 F.2d 1437, 1444-46, 223
USPQ 603, 606-08 (Fed. Cir. 1984). To qualify as prior art under
pre-AIA 35 U.S.C.
102(g)
, however, there must be evidence that the subject matter was
actually reduced to practice, in that conception alone is not sufficient. See
Kimberly-Clark,
745 F.2d at 1445, 223 USPQ at 607. While the filing
of an application for patent is a constructive reduction to practice, the filing of an
application does not in itself provide the evidence necessary to show an actual reduction
to practice of any of the subject matter disclosed in the application as is necessary to
provide the basis for an
ex parte
rejection under
pre-AIA 35 U.S.C.
102(g)
Clark,
745 F.2d at 1445, 223 USPQ at 607. While the filing
of an application for patent is a constructive reduction to practice, the filing of an
application does not in itself provide the evidence necessary to show an actual reduction
to practice of any of the subject matter disclosed in the application as is necessary to
provide the basis for an
ex parte
rejection under
pre-AIA 35 U.S.C.
102(g)
. Thus, absent evidence showing an actual reduction to practice
(which is generally not available during
ex parte
examination), the
disclosure of a United States patent application publication or patent falls under
pre-AIA 35 U.S.C.
102(e)
and not under
pre-AIA 35 U.S.C. 102(g)
.
Cf.
In re Zletz,
893 F.2d 319, 323, 13 USPQ2d 1320, 1323 (Fed. Cir. 1989)
(the disclosure in a reference United States patent does not fall under
pre-AIA 35 U.S.C.
102(g)
but under
pre-AIA 35 U.S.C. 102(e)
).
In addition, subject matter qualifying as prior art only under
pre-AIA 35 U.S.C.
102(g)
may also be the basis for an
ex parte
rejection under
pre-AIA
35 U.S.C. 103
. See
In re Bass,
474 F.2d 1276,
1283, 177 USPQ 178, 183 (CCPA 1973) (in an unsuccessful attempt to utilize a
37 CFR
1.131
affidavit relating to a combination application, the inventors
admitted that the subcombination screen of a copending application which issued as a patent
was earlier conceived than the combination).
Pre-AIA 35 U.S.C. 103(c)
, however,
states that subsection
-AIA
35 U.S.C. 103
. See
In re Bass,
474 F.2d 1276,
1283, 177 USPQ 178, 183 (CCPA 1973) (in an unsuccessful attempt to utilize a
37 CFR
1.131
affidavit relating to a combination application, the inventors
admitted that the subcombination screen of a copending application which issued as a patent
was earlier conceived than the combination).
Pre-AIA 35 U.S.C. 103(c)
, however,
states that subsection
(g)
of
pre-AIA 35 U.S.C. 102
will not preclude
patentability where subject matter developed by another person, that would otherwise
qualify under
pre-AIA 35
U.S.C. 102(g)
, and the claimed invention of an application under
examination were owned by the same person, subject to an obligation of assignment to the
same person, or involved in a joint research agreement, which meets the requirements of
pre-AIA 35 U.S.C.
103(c)(2) and (c)(3)
, at the time the invention was made. See
MPEP §
2146
.
For additional examples of
pre-AIA 35 U.S.C. 102(g)
issues such as
conception, reduction to practice and diligence outside the context of interference
matters, see
In re Costello,
717 F.2d 1346, 219 USPQ 389 (Fed. Cir.
1983) (discussing the concepts of conception and constructive reduction to practice in the
context of a declaration under
37 CFR 1.131
), and
Kawai v.
Metlesics,
480 F.2d 880, 178 USPQ 158 (CCPA 1973) (holding constructive
reduction to practice for foreign priority under
35 U.S.C. 119
requires meeting the
requirements of
35 U.S.C.
101
and
35 U.S.C. 112
).

## Nearby sections

- [MPEP § 2103 Patent Examination Process](https://www.frixlaw.com/law-library/statutes/MPEP_S2103.md)
- [MPEP § 2104 Requirements of 35 U.S.C. 101](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.md)
- [MPEP § 2104.01 Barred by Atomic Energy Act](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.01.md)
- [MPEP § 2105 Patent Eligible Subject Matter — Living Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2105.md)
- [MPEP § 2106 Patent Subject Matter Eligibility](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.md)
- [MPEP § 2106.01 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.01.md)
- [MPEP § 2106.02 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.02.md)
- [MPEP § 2106.03 Eligibility Step 1: The Four Categories of Statutory Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.03.md)
- [MPEP § 2106.04 Eligibility Step 2A: Whether a Claim is Directed to a Judicial Exception](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04.md)
- [MPEP § 2106.04(a) Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a).md)
- [MPEP § 2106.04(a)(1) Examples of Claims That Do Not Recite Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(1).md)
- [MPEP § 2106.04(a)(2) Abstract Idea Groupings](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(2).md)
- [MPEP § 2106.04(a)(3) Tentative Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(3).md)
- [MPEP § 2106.04(b) Laws of Nature, Natural Phenomena & Products of Nature](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(b).md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S2138. Check the current official text before relying on it. Not legal advice.