Long term outcome of osteochondritis dissecans of the humeral capitellum was determined for 53 patients. The average age of the patients at the time of treatment was 16.6 years (range, 10-34 years). The average followup was 12.6 years (range, 3-25 years). Seven of 14 (50%) patients who were treated conservatively and 18 of 39 (46%) who were treated by surgical removal of the fragment were found to have residual elbow symptoms associated with daily living activities (poor outcome). The initial radiographs of the elbow were available for 45 patients; a poor outcome was seen in six of 19 (32%) early lesions and 13 of 26 (50%) advanced lesions. Fourteen elbows had evidence of osteoarthritis on the initial radiographs, and a poor outcome was seen for nine (64%) of these elbows. After removal or detachment of the fragment, seven osteochondral defects were assessed as large, and all seven had a poor outcome. These long term results suggest that the residual elbow symptoms associated with daily living activities in approximately 50% of patients may be associated with advanced lesions, osteoarthritis of the elbow, and a large osteochondral defect.