MPEP 2012.01
Collateral Estoppel

Ninth Edition of the MPEP, Revision 10.2019, Last Revised in June 2020

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2012.01    Collateral Estoppel [R-08.2017]

[Editor Note: This MPEP section is only applicable to reissue applications filed before September 16, 2012. For reissue applications filed on or after September 16, 2012, the requirement to state that the errors arose "without any deceptive intention" was eliminated consistent with the America Invents Act (AIA) amendments to 35 U.S.C. 251.]

The Supreme Court in Blonder-Tongue Labs., Inc. v. Univ. of Ill. Found., 402 U.S. 313, 169 USPQ 513 (1971) set forth the rule that once a patent has been declared invalid via judicial inquiry, a collateral estoppel barrier is created against further litigation involving the patent, unless the patentee-plaintiff can demonstrate "that he did not have" a full and fair chance to litigate the validity of his patent in "the earlier case." See also Ex parte Varga, 189 USPQ 209 (Bd. App. 1973). As stated in Kaiser Industries Corp. v. Jones & Laughlin Steel Corp., 515 F.2d 964, 987, 185 USPQ 343, 362 (3rd Cir. 1975):

In fashioning the rule of Blonder-Tongue, Justice White for a unanimous Court made it clear that a determination of patent invalidity, after a thorough and equitable judicial inquiry, creates a collateral estoppel barrier to further litigation to enforce that patent.

Under pre-AIA 35 U.S.C. 251, the Director can reissue a patent only if there is "error without any deceptive intention." The Director is without authority to reissue a patent when "deceptive intention" was present during prosecution of the parent application. See In re Clark, 522 F.2d 62, 187 USPQ 209 (CCPA 1975) and In re Heany, 1911 C.D. 138, 180 (1911). Thus, the collateral estoppel barrier applies where reissue is sought of a patent which has been held invalid or unenforceable for "fraud" or "violation of duty of disclosure" in procuring of said patent. It was held in In re Kahn, 202 USPQ 772, 773 (Comm’r Pat. 1979):

Therefore, since the Kahn patent was held invalid, inter alia, for "failure to disclose material facts of which * * * [Kahn] was aware" this application may be stricken under 37 CFR 1.56 via the doctrine of collateral estoppel as set forth in Blonder-Tongue, supra.


The Patent and Trademark Office... has found no clear justification for not adhering to the doctrine of collateral estoppel under Blonder-Tongue in this case. Applicant has had his day in court. He appears to have had a full and fair chance to litigate the validity of his patent.

See MPEP § 2259 for collateral estoppel in reexamination proceedings.