Objective: The aim of this study was to investigate the influence of perioperative blood transfusion on the subsequent course of Crohn's disease. Design: Retrospective investigation of 158 consecutive patients with Crohn's disease diagnosed between 1962 and 1982. The patients were followed until 1988 with a median follow-up time of 5.8 years (range 0-23). Methods: Actuarial analysis of outcome was performed. Groups were compared by log-rank test and Mann-Whitney test. Results: Forty-eight patients had at least one blood transfusion from 30 days before, to 30 days post-surgical intervention. The cumulative risk of recurrence within 5 years after the first resection was 43% [95% confidence limits (CI) 29-56] in patients receiving transfusion and 33% (95% CI 14-52) in the non-transfused group of patients (NS). Conclusion: The results of this study do not support the hypothesis that perioperative blood transfusion in patients who undergo surgery for Crohn's disease prevents relapse.