43 U.S.C. § 1166
Section 1166 · Limitations of suits to annul patents
Amended 1 time on record
Applied in 22 court decisions — leading case Putnam v. Ickes (1935)
Most recently applied in Voisin v. United States (January 2008)
How often courts cite this section
Court decisions citing this, by year.Markers show enactment, consequential amendments, and circuit splits over this section — watch for a citation surge after a change or a disagreement. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
Suits by the United States to vacate and annul any patent shall only be brought within six years after the date of the issuance of such patents.