In an unselected series of 207 consecutive patients with Crohn's disease diagnosed between 1958 and 1974, 170 underwent a resection of all the macroscopically involved bowel ('radically' resected). Two patients died during the first postoperative month. The crude recurrence rate for the surviving 168 patients was 49%. The cumulative recurrence rate, calculated by the actuarial method, was 53% at 15 years. Age, sex, length of preoperative disease history, localization of the lesions in the bowel, and primary surgical procedures performed had no influence on the recurrence rate. However, the histopathological appearance of the resection margins seemed to influence the prognosis, since the presence of ulcers and/or granulomas was correlated with a significantly increased recurrence rate.