BACKGROUND: This study was performed to investigate the clinical usefulness of combined autotransfusion using preoperative autologous donation(PAD) and acute normovolemic hemodilution(ANH) compared with autotransfusion using only PAD in 30 patients undergoing spinal surgery(posterior decompression and fusion). METHODS: Control group(n=15) were transfused with PAD(3 units), and received intra- and postoperative autotransfusion. Combined group(n=15) received ANH(2 units) in addition to above 3 methods applied to control group. Patients were not allowed to predonate or receive ANH if their Hct were below 34%. We applied induced hypotension only to the control group. RESULTS: There were no significant differences between groups in perioperative Hb and Hct levels. Mean volume of autologous blood salvaged by cell saver was significantly greater in combined group(710 ml) than in control group(288 ml). Besides autologous blood, 2.33 units(mean) of homologous blood were used postoperatively in 3 patients of control group and 2 units(mean) of predonated blood were unused and discarded in 3 patients of combined group. CONCLUSION: It appears that combined autotransfusion using PAD and ANH is useful and it increases success rate of autotransfusion.