In 2010, Major League Baseball and the Major League Baseball Players Association reached an agreement regarding the development and implementation of an electronic medical record system and a new league-wide injury surveillance system. The systems were developed to create a more efficient method to track medical histories of players longitudinally as they move across Major and Minor league affiliates, as well as to identify and monitor injury trends in the sport, identify areas of specific concern, and conduct epidemiologic research to better optimize player health and safety. The resulting injury surveillance system, the Health and Injury Tracking System (HITS), is a robust system that includes all players from the both the Major and Minor Leagues. HITS also allows for data linkage with other player- and game-level data to inform the development of injury prevention policies and programs. In the present article, we document the development and implementation of HITS; describe its utility for epidemiologic research; illustrate the potential analytic strength of the surveillance system and its ability to inform policy change; and note the potential for this new surveillance system to advance the field of sports injury epidemiology.