The effect of perioperative blood transfusion on the recurrence of Crohn's disease is controversial. Various studies have suggested that perioperative blood transfusions reduce the risk of recurrence; others have failed to find a protective effect. Since all the studies are based on relatively small numbers, we performed a pooled analysis. We contacted the senior authors of seven previously published studies and asked for the original data. Four authors provided their data. The pooled database included 622 patients with a primary and complete resection of macroscopic disease. Recurrence was defined as the need for repeat surgery for disease control. Kaplan-Meier life table analysis was performed. Of the study sample, 366 cases (59%) were female. Disease distribution was as follows: small bowel (47%), small/large bowel (35%), and large bowel only (18%). Three hundred thirty-one patients (53%) received blood in the perioperative period. Mean follow-up was 72.8 months. For the overall sample, the 5-year recurrence rates were 26.9% for the transfused group and 25.2% for the nontransfused (p = 0.456). When the data were stratified by age, gender, disease location, and length of resection, no difference in 5-year recurrence rates between transfused and nontransfused cases could be detected. In this pooled analysis of four retrospective studies on the effect of blood transfusions on the risk of recurrence in Crohn's disease, we were unable to document a protective effect.