The results of the operative treatment of medial epicondylitis in forty consecutive elbows (thirty-eight patients) were assessed retrospectively on the basis of the subjective outcome, pain noted during resisted palmar flexion of the hand and wrist, satisfaction of the patient, and grip strength. The mean age of the patients at the time of the operation was forty-two years (range, twenty-two to fifty-six years). Coexistent ulnar neuritis was identified preoperatively in twenty-four elbows. The operative procedure involved release of the attachment of the common flexor muscle of the forearm at the medial epicondyle in all of the elbows and release of the retinaculum over the cubital tunnel in seventeen of the twenty-four elbows that had coexistent ulnar neuritis. The patients were followed for a mean of forty-four months (range, twenty-four to sixty-seven months). Twenty-five elbows had a good over-all subjective outcome. The preoperative pain had resolved in twenty-eight elbows. The over-all subjective outcome was less favorable for the elbows that had had coexistent ulnar neuritis (p < 0.05). Eleven of the sixteen elbows that had had isolated medial epicondylitis and had been treated with a flexor release were free of symptoms at the time of follow-up, compared with only three of the twenty-four elbows that had had coexistent ulnar neuritis. This difference was significant (p < 0.01). Moreover, in fifteen elbows, the symptoms of ulnar neuritis persisted. There was no difference in grip strength between the treated and contralateral extremities.(ABSTRACT TRUNCATED AT 250 WORDS)