In United States law, an infringement may occur where the defendant has made, used, sold, offered to sell, or imported the infringing invention or its equivalent.

In U.S. law, no infringement action may be started until the patent is issued. However, pre-grant protection is available in the U.S. In the U.S., 35 USC 154(d) allows for a patent applicant to obtain a reasonable royalty for infringing activities before a patent is granted. This right to obtain provisional damages requires a patent holder to show that the infringing activities occurred after the publication of the patent application 18 months from filing, that the published application is substantially identical to the eventually granted patent, and that the infringer has ``notice`` of the published patent application.

Direct infringement

A person directly infringes a patent by making, using, offering to sell, selling, or importing into the US any patented invention, without authority, during the term of the patent.

Indirect infringement

Under certain jurisdictions, there is a particular case of patent infringement, called ``indirect infringement``. This can occur for instance when a device is claimed in a patent and when a third party supplies a product which can only be reasonably used to make the claimed device. In the U.S., types of ``indirect infringement`` include ``contributory infringement`` and ``induced infringement``.

In the United States, 35 U.S.C. § 271(b) defines (active) induced infringement: ``Whoever actively induces infringement of a patent shall be liable as an infringer.``

Active inducement of infringement

Under 35 U.S.C. Section 271(b), ``whoever actively induces infringement of a patent shall be liable as an infringer.`` Thus, by selling products that only has use if used in an infringing way, the seller could be found liable for the direct infringement of the end user. This provision typically protects against those who aid and abet end users. National Presto Indus., Inc. v. West Bend Co., 76 F.3d 1185, 1195 (Fed. Cir. 1996). Further, there can be no inducement if there is not first a showing of direct infringement. Fuji Mach. Mfg. Co. v. Hover-Davis, Inc. 60 F.Supp. 2d 111, 117 (W.D.N.Y. 1999).