To compare the time course of clinical recurrences and reoperations following primary resections for fistulization versus fibrostenotic obstruction in ileal Crohn's disease, we performed a retrospective cohort study of 71 patients undergoing their first resection at The Mount Sinai Hospital between 1961 and 1984. Among these 71 patients, 35 were classified as fistulizing and 36 as fibrostenotic. Follow-up was 93% complete through 1990, with a median follow-up of 73 months to reoperation and 105 months to last contact. The fistulizing and fibrostenotic patients experienced virtually identical numbers of clinical recurrences: 25 from the former group and 24 from the latter. The recurrences appeared very slightly earlier among the fistulizing than among the fibrostenotic group, but the difference did not approach statistical significance. Only 18 patients came to reoperation during follow-up: 12 from the fistulizing and 6 from the fibrostenotic group. The earliest reoperation in the fistulizing group occurred at 14 months and in the fibrostenotic group at 44 months. There was a trend for earlier reoperation in the fistulizing group, but the difference was not statistically significant. Different clinical patterns of Crohn's disease have yet to be correlated with distinctive subclinical biologic markers.