To evaluate the effect of blood transfusion on incidence of postoperative hepatitis and prognosis of gastric cancer, the data of 493 patients having been operated on curatively in our hospital were divided into two groups: those who received transfusion before the beginning of components transfusion and those who received transfusion after that. The data indicated that the incidences of postoperative hepatitis increased from 3.7% to 5.4% after the beginning of transfusion of blood components, but the 5-year survival rates did not differ significantly. The 5-year survival rates of transfused patients and non-transfused patients were 57%, 84%, respectively (p less than 0.001) and the rates decreased according to the dose of whole blood and/or packed red cells. The same results were obtained when limited to stages I + II, But they were not deteriorated by fresh frozen plasma significantly. The result suggests that it is better to refrain from unnecessary blood transfusion and transfuse whole blood in the case of massive transfusion to decrease the incidence of postoperative hepatitis and more better to transfuse leucocyte-free blood to avoid immunological effect.