Influences of operative stress, shock, anoxia and/or liver damage upon the disturbances in blood clotting following massive transfusion of preserved blood were investigated experimentally. None of coagulation factors were so disturbed to invite a hemorrhagic tendency only by one of them. Qualitative and quantitative decrease in platelets and decrease in AHG level were thought to be caused by massive preserved blood transfusion itself. Decreases in prothrombin and labile factor following preserved blood transfusion were much intensive in case of accompanying with operative stress, shock, anoxia or liver damage. It was surmized that the occurrence of fibrinolysis had an imptortant part to cause the decrease in clotting factors.