Traumatic avulsion of the flexor digitorum profundus tendon or "jersey" finger is uncommon. Twenty patients have been reviewed at an average follow-up of seven years. Patients were seen less than three weeks from trauma in two-thirds of the cases, whereas in one third it was later. Loss of active flexion of the distal interphalangeal joint was the main complaint. Pure avulsions seen less than three weeks from the injury were all reinserted except one (10 out of 11). When the tendon avulsion was associated with a bone fragment (three cases), an osteosynthesis with K-wires was performed. Patients seen more than three weeks from the injury were treated with tendon resection in six, with a capsulodesis in four, and with a palmaris longus tendon graft in one. All reinsertions of the flexor digitorum profundus tendon performed less than three weeks from injury gave satisfactory results but a secondary rupture was observed in two. Satisfactory results were also obtained after avulsion of the tendon associated with bone fracture, but one patient developed osteoarthritis. Three out of five patients operated more than three weeks following the injury with tendon resection had satisfactory results. The patient with a palmaris longus tendon graft obtained an unsatisfactory result.