During a period of six years, 765 consecutive patients were treated by the trauma service at Allegheny General Hospital for closed mid-shaft femur fractures that were a component of their injury complex. Thirty-one patients underwent angiography of the involved extremity for indications including loss of pulses in eleven and large hematomas or deformities of the thigh in the remainder. Ten patients (1.3%) were found to have acute vascular injuries. In nine patients there was an intimal flap of the superficial femoral artery (SFA), and in one, a pseudoaneurysm. Two patients had injuries of the femoral nerve. Three patients had no other associated major injuries (Injury Severity Score range, 10-19). Twelve months after the initial injury, one patient developed an arteriovenous fistula of the SFA. Detailed, repeated physical examinations, early utilization of angiography, and intensive follow-up by the trauma surgeon or orthopedic surgeon of patients with closed mid-shaft femur fractures should lead to early recognition of this potentially serious association.