We performed a retrospective review of the long-term results of operative treatment of medial epicondylitis in thirty elbows (twenty-six patients). Sixteen elbows had concomitant ulnar neuropathy. All of the patients had tenderness over the medial epicondyle. The most sensitive provocative maneuver was resisted pronation of the forearm (a positive result for twenty-eight elbows), followed by resisted flexion of the wrist (a positive result for twelve elbows). The operative findings included an inflammatory focus in seventeen elbows and focal ulnar-nerve compression in nine. Debridement of the origin of the flexor-pronator tendon mass, with decompression or transposition of the ulnar nerve when indicated, was associated with an 87 per cent rate (twenty-six elbows) of good or excellent results at an average of seven years (range, two to fifteen years) after the operation. Twenty-four of the twenty-five elbows that had no or mild associated ulnar neuropathy (type-IA or IB medial epicondylitis) had a good or excellent result, while two of the five elbows that had moderate or severe associated ulnar neuropathy (type-II medial epicondylitis) had a good or excellent result. This difference was significant (p = 0.009). Nine patients (nine elbows) needed more than six months before maximum improvement was obtained.