Thirteen patients were operated for cubital tunnel syndrome and followed for an average of 26 months postoperatively. Ten patients had a history of relevant trauma and three patients had degenerative osteoarthritis of the elbow. The average duration of symptoms was 18 months (range, 2 to 96 months). Diagnosis was made by physical examination, electromyography and nerve conduction study. Among these, nerve conduction study was found to be the most valuable diagnostic method for the patients with atypical clinical findings. Most of the operations were performed by anterior transposition of the ulnar nerve. At the most recent follow-up, the result was excellent in two patients, good in eight, and fair in three; thus ten patients(77%) showed satisfactory results. The rating system for ulnar neuropathy based on sensory, motor dysfunction and pain was useful for evaluating the operative results. The postoperative gain of score for pain and sensory function were larger than that of motor function. Factors known to influence the result of the operation (age, duration of symptom, history of trauma, method of operation) did not effect the outcome in this study. For successful operation, the ulnar nerve must be thoroughly examined, all possible levels of compression must be released and new foci of compression must be created.