In order to determine whether perioperative blood transfusion affects the recurrence of Crohn's disease, the authors reviewed the records of 79 patients with Crohn's disease who underwent their initial intestinal resection at their institution. Recurrence of Crohn's disease was documented by radiographic studies, endoscopy, or laparotomy. During the hospital admission for resection, 45 patients received multiple red blood cell transfusions. Recurrence developed in 22 percent of these patients by 36 months, and the median time to recurrence was 35 months. In the 34 patients who did not receive multiple transfusions, recurrence was found in 44 percent by 36 months, and the median time to recurrence was 20 months. These differences are significant, using the Kaplan-Meier analysis (P less than 0.04). Recurrence in patients with disease limited to the small bowel or to the colon was not significantly affected by the transfusion status. However, recurrence developed in only 10 percent of multiply transfused patients with ileocolic disease by 36 months, whereas recurrence developed in 45 percent of the patients who were not multiply transfused. (Significance, P = 0.057). The authors believe that the observed decreased rate of recurrence of Crohn's disease in patients receiving multiple perioperative transfusions may represent another example of clinically significant immunosuppression from blood transfusion.