In this article, the six major studies of soccer injury epidemiology are reviewed. Strengths and weaknesses of each epidemiologic design are critiqued and the crucial importance of the definition of injury is emphasized. The effect of age, sex, and intensity of play on injury rates is discussed. Our present knowledge of injury rate by anatomical site, player position, and the type of playing surface are reviewed. We examined the importance of player factors such as flexibility, joint laxity, weakness, and incomplete rehabilitation from other injuries. In addition, we reviewed the role played by inadequate equipment, field conditions, and rule violations. A successful program for soccer injury prevention is described, and guidelines for future soccer injury epidemiology research are proposed.