The principal benefit of using autologous blood is avoidance of complications associated with conventional homologous blood transfusion such as viral infections, immunosuppression, and allogenic immunization. Since December 1991, a ruling of the Federal Supreme Court has obliged physicians to disclose to their patients the risk of contracting an infection from an intraoperative or postoperative blood transfusion and the possibility of donating their own blood for transfusion into them later. Of 263 patients with localized prostate cancer who underwent radical retropubic prostatectomy, 194 (73.8%) elected to have their blood collected for possible transfusion. Of the patients who needed transfusion, 80.7% received only autologous blood and haemodilution for substitution of haemoglobin. Nearly all patients with blood loss below 1,500 ml used only autologous blood transfusions during their operations. Increasing the number of units of autologous blood collected decreases the likelihood that homologous blood will be needed and thus the risks associated with transfusion of homologous blood.