What is a Section 15 Affidavit of Incontestability?
Five years after a mark has been registered, the registrant may apply to have the mark declared “incontestible” by filing a section 15 affidavit. Possession of an incontestible mark is conclusive evidence of the registrant’s exclusive right to use that mark on the type of goods in question, subject only to certain defenses that are listed in section 33(b) of the Lanham Act. Thus, incontestability has two practical implications. First, it immunizes the registrant from certain claims that the mark is invalid when a third party seeks to have the mark canceled. Second, when the holder of federal registration files suit for infringement, incontestability will also preclude the infringing defendant from asserting defects in the mark as defenses. The most important challenges to the mark cut off by incontestability are (1) that the registrant is not the senior user of the mark and (2) that the mark itself is merely descriptive and lacks secondary meaning.
