The reduction of homologous blood transfusions remains an important goal. The actual blood loss and the positive fluid balance during cardiac operations involving CPB result in a fall in the haematocrit and represent major risk factors for blood transfusions. Methods and techniques which lead to a decrease of haemodilution are important when aiming at fewer transfusions in such operations. Considering volume load as modifiable, a number of efforts have been made to reduce the resulting positive fluid balance under CPB. The minimization of the prime volume with or without the use of hyperoncotic solutions is crucial in the attenuation of haemodilution. The beneficial effect of minimized circuits on inflammation and haemodilution and the retrograde autologous priming of the cardiopulmonary bypass circuit have a positive result in a reduce need for allogeneic blood. Autologous blood cell salvage and intraoperative autotransfusion decreases requirements for homologous blood. Experience in these techniques increases their effectiveness and reduces their possible dangers. A multimodal approach and change in physician transfusion practices is deemed necessary for reducing homologous blood transfusion during cardiac operations.