In this lecture from Yale's Introduction to Medical Software, the instructor explains the regulatory process required to bring medical software to market safely and legally in the United States. The session walks through how software intended for use as or within a medical device is classified and reviewed, and what developers must demonstrate to the FDA regarding safety and effectiveness before release. The lecture covers the practical implications of regulatory classification for a development team's design and documentation choices from the outset of a project. It gives students a concrete picture of how compliance requirements intersect with engineering work, building on the course's introductory lessons on regulation and risk in medical software development.