We could report the effect of the autologous blood transfusion to the lobectomy, by comparison with no-blood transfusion group and MAP-red cell concentrate transfused group (MAP group). Autologous blood which was stored three days before an operation and preserved at 4 degrees C kept 89.9 +/- 11.7% of the number of erythrocyte and 59.6 +/- 23.4% of platelet. Autologous blood transfusion group and MAP group showed significantly more than no-blood transfusion group on the number of erythrocyte at the time of discharge. These facts suggest that the autologous blood has an ability of coagulation. We concluded that on lobectomy autologous blood transfusion was better than MAP-red cell concentrate transfusion in point of protection from disease transmission and better than no-blood transfusion in point of post-operative recovery.