The purpose of this study was to evaluate the results of excision of the ulnar slip of the flexor digitorum superficialis tendon, with or without A1 pulley release, for the treatment of trigger finger in diabetic patients. We performed a retrospective review with long-term follow-up examinations. Short-term data was obtained on 18 consecutive patients (37 fingers). Long-term information was collected on 14 of these patients (24 fingers) at an average of 48 months after surgery. Short-term follow-up revealed average proximal interphalangeal joint (PIP) flexion of 81°. One patient had slight residual triggering. At long-term follow-up, 93% of patients were completely or very satisfied with the procedure. Total active finger motion averaged 218°, and PIP extension deficit averaged less than 5°. Pinch strength was equal to the contralateral corresponding finger. There were no significant complications. One finger had minimal residual triggering. In conclusion, this procedure is a safe and effective treatment for the often-difficult problem of stenosing flexor tenosynovitis in the diabetic patient.