A case of isolated traumatic avulsion of the tendon of extensor carpi radialis longus (ECRL) is described. Surgical repair was attempted 12 days later, but an early contracture of the muscle was encountered. The tendon could not be pulled down to its insertion and was sutured side to side to the tendon of extensor carpi radialis brevis (ECRB). A year later the patient had residual weakness of wrist extension and hand grip. The likely cause of the early contracture of the muscle and the need for early and accurate reposition of extensor carpi radialis longus tendon are described.