It is well documented that autotransfusion can reduce or eliminate the use of homologous blood. And recently many studies have shown that autotransfusion influences postoperative course so that patients transfused with autologous blood show less tumor recurrence rate or less wound infection rate than those transfused with homologous blood. So we conducted a study on autotransfusion compared with homologous transfusion in patients undergoing posterior spinal fusion procedures. Autotransfusion group consisted of predonation and hemodilution group. In predonation group (n=20), autotransfusion was performed by autologous preoperative donation, intraoperative salvage using Cell saver and postoperative salvage using Orth-evac drainage/ reinfusion device. In hemodilution group (n=20), autotransfusion was performed by acute normo-volemic hemodilution and intraand postoperative autotransfusion methods same as predonation group. Above autotransfusion group was compared with homologous transfusion group (n=20) on perioperative CBC (complete blood count) changes, amount and duration of postoperative drainage, transfusion side effects and complications associated with operation. Results are as follows, 1) 90% of patients in autotransfusion group could complete transfusion therapy without the use of homologous blood. 2) Total amounts of transfused blood were 1,733±567 ml (5.4+1.8 units) in predonation group, 1,539±712 ml (4.8+2.2 units) in hemodilution group and 4.7±1.3 units in homologous transfusion group. There is no statistically significant difference between autotransfusion and homologous transfusion group. 3) In predonation group, hemoglobin and hematocrit levels were significantly lower than those of homologous transfusion group preoperatively and at PAR (postanesthetic recovery), 2nd day and 7th day postoperatively. But at 14th day, the levels were recovered as high as those in homologous transfusion group. 4) In autotransfusion group, total amount and the duration of postoperative drainage were significantly less and shorter respectively than those of homologous transfusion group. 5) In homologous transfusion group, 60% of patients experienced one or more than one of transfusion side effects and one patient received emergency operation of hematoma evacuation immediate postoperatively. In autotransfusion group, 47.5% of patients showed fever above 38degree Centigrade, and all of which were associated with the use of postoperative autotransfusion but other complications associated with transfusion or operation could not be found. In conclusion, we think autotransfusion not only can reduce or eliminate the use of homologous blood but also seems to have beneficial influences on postoperative recovery.