Nine patients with distal biceps tendon ruptures that had been repaired anatomically with a double-incision technique were evaluated. All patients were men, whose average age was 46 years old (range, 31-66 years). Three patients injured their dominant extremity and 6 their nondominant extremity. This represents the largest series of operatively treated nondominant biceps ruptures with quantitative followup in the literature. All patients responded to a questionnaire, and had clinical, radiographic, and isokinetic testing. The average followup was 30 months (range, 12-57 months). Patients were pleased uniformly with their operative results, and all would have had surgery given the option again. Strength testing results of the dominant extremities revealed full return of forearm supination strength and elbow flexion strength. Endurance data also revealed full return when compared with controls. In nondominant extremities, a 14% supination strength deficit from expected values (corrected for dominance) and a 14% flexion strength deficit (also corrected) were observed in the 6 patients. A radioulnar synostosis that required resection developed in 1 patient. Anatomic repair of distal biceps tendon rupture gives consistently good results. Dominant extremities can achieve normal function, whereas nondominant extremities may require aggressive therapy to achieve maximal strength.