The postoperative recurrence rates for Crohn's colitis (CC) and ulcerative colitis (UC) have varied markedly in different medical centers. We have reviewed the reasons for this variation and present our own series of patients in a manner which allows comparison with previous studies. In our study: 1) Patients with CC had an overall recurrence rate of 38% after total colectomy. By actuarial statistics, this recurrence rate computes to 48% by 12 years after operation. 2) Patients with ileal disease, even if totally removed at operation, had a recurrence rate of 48% whereas those with no obvious ileal involvement had a recurrence rate of 18%. 3) When nonspecific criteria are used for recurrence, which we call "complication," as has been the case in several previous studies of CC, even patients with UC had a complication rate of 33%. Such complications both in UC and CC represent postoperative occurrence rather than ileal recurrence of the inflammatory process. 4) Patients with CC develop more postoperative complications than patients with UC, but for most of the time they were asymptomatic. In this series there were no patients with disease originally or almost entirely limited to the colon who became "intestinal cripples" as a result of recurrent disease. 5) Patients with short preoperative intervals had the highest recurrence rate, whereas patients with disease of the terminal ileum had the highest postoperative complication rate. 6) Patients with "superficial" CC had a low recurrence rate, probably because of a shorter follow-up than the other patients. There were no true recurrences in patients with UC.