Stress fractures are one of the most common overuse injuries seen in athletes, accounting for up to 20% of all injuries presented to sports medicine clinics. Runners are particularly prone to these injuries, however, it is difficult to predict injury as there is usually a critical interplay between the athlete's biomechanical predisposition, training methods, and other factors such as diet, and muscle strength and flexibility. This article will discuss the key clinical findings for the majority of stress fractures encountered in a sports medicine practice. A classification scheme will also be described that will allow the clinician to make appropriate treatment decisions based on the degree of risk for each injury.