A freedom-to-operate search or infringement search, is a search done on issued patents or on pending patent applications to determine if a product or process infringes any of the claims of the issued patents or pending patent applications.

A freedom-to-operate may also include expired art that acts as a ‘safe harbor’ permitting the product or process to be used based on patents in the public domain. These searches are often performed by a patent attorney or a professional patent searcher who is under the direction of the patent attorney.

A freedom-to-operate can be followed by a infringement/noninfringement opinion, i.e. a legal opinion provided as to whether a given product or process infringes/does not infringe the claims an issued patent or pending patent application.

A noninfringement opinion (setting forth reasons the patent is not infringed, or providing other defenses such as prior use, intervening rights, or prior invention) is also possible.