Among 615 patients with Crohn's disease originally diagnosed at the Cleveland Clinic Foundation from 1966 to 1969, 592 have been followed (96%) for a mean of 13 yr. Of these, 438 had undergone operation. The purpose of this study was to determine how many of these patients had developed recurrences requiring another operation and to relate recurrences to the original anatomic location of disease (the clinical pattern) and surgical indication. Those patients with ileocolic disease had the highest recurrence: 53% compared with 45% for colonic and 44% for small intestinal patterns. Second recurrences were ileocolic pattern 35%, colon 34%, small intestine 38%. The estimated median time of recurrence was similar among these three groups. The presence of internal fistula or perianal disease as an indicator for surgery were associated with a higher likelihood of recurrence and a shortened estimated median time to recurrence. This study supports the concept of conservatism with regard to the management of these two complications for patients with Crohn's disease.