Thirteen patients who had Crohn's disease of the colon and rectum were treated surgically by a diverting colostomy or ileostomy. Primary indications for surgery were severe perianal complications in eight patients, retardation of growth and development in two, and failure of medical management to effect a satisfactory remission in three. Improvement in clinical condition has occurred in all patients, but four have subsequently undergone proctocolectomy because perirectal complications, particularly perianal and rectovaginal fistulas, persisted or worsened. Two patients have had intestinal continuity reestablished by closure of colostomy. One has had recurrence which required further surgery, and the other one has remained well. In the remaining seven patients the symptoms and signs of Crohn's disease have not subsided completely.