Aim:To study the relationship between postoperative infections in the patients with gastrointestinal carcinomas and blood transfusion and its composition. Methods: Various factors of postoperative infections in 281 cases of gastrointestinal carcinomas were retrospectively analyzed. Results: A total of 117 cases underwent perioperative transfusion. The postoperative infection rate was 5.9% in 34 cases who were transfused white cell filtering blood and 36.1% in 83 cases who were transfused whole blood or packed red cell. And in 164 cases without perioperativel transfusion, the postoperative infection rate was only 4.3%. There were significant differences in the infection rates between the tranfusion groups and the controls ( P 0.05). The results demonstrated that postoperative infection rate increased with the amount of transfusion. Conclusions: The postoperative infection complications relate to transfusion, blood composition and the amount of transfusion. So if the patients can safely undergo an operation, transfusion should not be given or give as less as possible. If transfusion is needed for a patient, it is best to give white cell filtering blood and improve transfusion quanlity to prevent postoperative infection.