A study was undertaken to document the incidence of overuse injuries sustained during basic military training. The injuries in military recruits (N = 1,261) undergoing basic training were documented prospectively over a 9-week period. Injury incidence was expressed as percentage of all recruits injured, weekly incidence (injuries/1,000 recruits/week), and injuries/1,000 training hours. The incidence of six common specific overuse injuries was also recorded. The overall incidence of injuries over the 9-week period was 31.9% (acute, 13.6%; overuse, 86.4%), or 1.8/1,000 training hours. The highest incidence of injuries was recorded in weeks 1 to 3 and week 9 of training, which were weeks characterized by marching ( > 77% of the training time). The highest incidence (injuries/1,000 training hours) of specific overuse injuries were tibial bone stress reaction (0.33), patellofemoral pain (0.22), and the iliotibial band friction syndrome (0.08). The incidence of stress fractures over the 9-week period was 1.2% (0.07/1,000 training hours). Injuries to the knee, lower leg, and ankle accounted for more than 80% of all injuries. A total of 3.6% of training days were lost during this period, mainly due to bone stress injuries. In order to reduce injuries during basic military training, attention must be directed towards (1) modifying the type of training and (2) prevention of bone stress injuries.