The hospital records of 69 autologous blood donors undergoing elective surgical procedures and those of matched controls were reviewed in an effort to assess whether autologous blood donation altered physician transfusion behavior. Physicians tolerated significantly lower admission (0.372 vs 0.437 [37.2% vs 43.7%]), nadir (0.304 vs 0.334 [30.4% vs 33.4%]), and discharge (0.326 vs 0.358 [32.6% vs 35.8%]) hematocrits in patients with autologous blood predeposits compared with matched controls. Additionally, 44 patients undergoing orthopedic procedures stored insufficient blood to prevent homologous blood exposure: ten of 17 patients could have avoided homologous blood if 4 U of autologous blood had been stored. Twenty-five patients undergoing nonorthopedic procedures stored an insufficient volume of blood to satisfy an unexpected transfusion need but were given transfusions of more than needed amounts of their own blood when transfusion was not clinically indicated. Future studies designed to maximize procurement of autologous blood are needed; a salutary effect on physician transfusion behavior would then be coupled with an autologous blood inventory that could eliminate homologous blood exposure in these patients.