This Practice Note discusses infringement claims arising in patent litigation under the Hatch-Waxman Act. Specifically, this Note addresses the legal requirements for Hatch-Waxman infringement claims, the safe harbor protections available for accused infringers, and the infringing act of submitting an Abbreviated New Drug Application (ANDA) to the Food and Drug Administration (FDA). This Note also addresses practical considerations for patent owners or New Drug Application (NDA) holders alleging infringement under the Hatch-Waxman Act and ANDA filers asserting a non-infringement defense.