When a mark has been in continuous use for five years after being placed on the Principal Register, it may be classified as incontestable, or immune from legal challenge. (37 United States Code, Section 1065.) Because of the fact that incontestability can be challenged on several grounds, the term “incontestable” really means “somewhat difficult to contest,” (as explained in more detail below).

A trademark owner seeking to make its mark incontestable must be able to demonstrate all of the following:

•  No final legal decision has issued against the mark.

•  No challenge to the mark is pending.

•  A Sections 8 and 15 Declaration describing the mark’s use was filed on a timely basis.

•  The mark is not and has not become generic.

In essence, achieving “incontestability status” conclusively establishes ownership of the mark for the uses specified in the Sections 8 and 15 Declaration that is filed between the fifth and sixth year after the mark is placed on the Principal Register.

The issue of whether a mark is incontestable usually arises in a lawsuit for infringement where the party being sued attempts to defend by challenging the validity of the plaintiff’s mark. If the plaintiff can establish that the mark is incontestable, the mark will be presumed valid unless the defendant can establish one or more of the following:

•  The registration or the incontestable right to use the mark was obtained by fraud.

•  The registrant has abandoned the mark.

•  The mark is used to misrepresent the source of its goods or services (for instance, use of the mark involves palming off).

•  The infringing mark is an individual’s name used in his or her own business, or is otherwise prohibited or reserved under the Lanham Act.

•  The infringing mark was used in commerce first—before the incontestable mark’s registration.

•  The infringing mark was registered first.

•  The mark is being used to violate the antitrust laws of the United States.

Even though an incontestable mark can still be challenged on these grounds, it is safe from attack on the otherwise common ground that it lacks distinctiveness. Thus, when Park ’N Fly, Inc. sued Dollar Park and Fly, Inc. for trademark infringement, the U.S. Supreme Court ruled that because the Park ’N Fly mark had obtained incontestability status, Dollar Park and Fly, Inc. could not allege as a defense that its rival’s mark is actually descriptive. (Park'N Fly v. Dollar Park and Fly 469 U.S. 189 (1985)).

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