Motocross has become a popular recreation activity in Southern California, particularly in the Inland Empire area. In order to evaluate the patterns of injury and outcomes associated with motocross accidents, the Trauma Registry data and charts of all patients with motocross-related injuries from January 2000 to December 2001 were reviewed. Of the 270 patients studied, 265 were males and 5 were females, with a mean age of 26 years (range, 5-61). The mean Injury Severity Score was 6.8 (range, 1-38). Injuries involved extremity trauma in 52 per cent of patients closed head injuries in 33 per cent, blunt chest trauma in 23 per cent, abdominal trauma in 15 per cent, spinal trauma in 14 per cent, and pelvic trauma in 8 per cent. Surgery was required in 96 patients (36%), most commonly for treatment of orthopedic injuries. After initial evaluation, 179 patients were admitted (66%), 60 were discharged home (22%), 29 were transferred for higher level of care (11%), and two expired (1%). The mean hospital length of stay was 2.3 days (range, 1-9). Motocross accidents are most commonly associated with extremity injuries and closed head trauma. Although the overall mortality is low, the morbidity is high, with a large proportion of patients requiring surgery.