Almost from the enactment of the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act (the FD&C Act) in 1976, the Food and Drug Administration (FDA or the Agency) has attempted to define with greater clarity when a change in a medical device would trigger the requirement that a manufacturer submit a new premarket notification (510(k)) to the Agency. This document supersedes FDA’s guidance Deciding When to Submit a 510(k) for a Change to an Existing Device (K97-1), issued on January 10, 1997. This guidance is not intended to implement significant policy changes to FDA’s current thinking on when submission of a new 510(k) is required. Rather, the intent of this guidance is to enhance the predictability, consistency, and transparency of the “when to submit” decision-making process by providing a least burdensome approach, and describing in greater detail the regulatory framework, policies, and practices underlying such a decision.