A prohibited act in regards to the use of another persons patent without their permission. Such permission is usually granted through a license.

In patent law, an infringement occurs when an individual or entity violates a patent owners exclusive right. Infringement can be done advertently or inadvertently, however either form can leave the infringer liable. The terms of a patent claim, as outlined in the patent specification, will inform the public of how restricted the terms of use of the patent are. It is therefore very important that thorough research is conducted before engaging in the use of material that could be potentially protected by law. It is important to note that as patents are territorial, infringement can only occur in countries where the patent has been granted.

Apple Inc v Samsung Electronics Co was a high profile case involving patent infringement in regards to smartphones and tablets. Samsung was granted a limited ban by the US International Trade Commission on certain Apple products being sold. While this decision was ultimately vetoed, patent infringements ultimately cost both organisations a large amount of financial resources and heartache.