Ruptures of the tendon of the biceps muscle usually occur spontaneously because of degeneration and almost always in the proximal tendon of the long head. Experiences of 13 patients with a rupture of the long head are described. Ten patients were treated by operation, the results of simple transposition of the tendon are excellent as long as ruptures have not existed for more than 6 weeks. The indication to operate ruptures of the long head is relative.