The purpose of this study is to report the functional outcome of the repair of a distal biceps tendon rupture by the use of the endobutton technique. We hypothesized that the endobutton provides excellent strength and clinical results after repair of distal biceps tendon rupture. Twenty-six patients underwent repair of biceps tendon ruptures by use of an endobutton for fixation of the biceps tendon stump to the radial tuberosity. There were 20 men and three women. The mean age was 52 years (39-75). The dominant side was involved in 11 patients. A partial rupture of the biceps tendon was found in four patients. The average delay in diagnosis was 16 days, with four patients presenting at six weeks or more after trauma. At an average follow-up of 16 months (6-48), 23 of 26 patients were available for follow-up and were examined clinically, radiologically, and by isokinetic testing. The average postoperative Mayo Elbow Performance Score (MEPS) was 94 points. The average Visual Analogue Scale (VAS) for pain was 1.5. Patients regained an almost full range of motion. Average flexion strength recovery was 80% and corresponding recovery of supination strength was 91%. Two patients developed asymptomatic heterotopic ossification seen on standard radiographs. In three patients, the endobutton had apparently disengaged without important difference in functional outcome. In one case, the endobutton had to be removed. There were no neurological complications. This study shows that a distal biceps tendon can be safely reattached to the radius by using the endobutton technique, yielding excellent and reproducible results. Level 4; Retrospective case series, no control group.