The retrospective study was undertaken to examine the impact of anemia developing during abdominal operations on oxygen transport and consumption. The concomitance of anemia and low reserves of the blood circulatory system was shown to be accompanied by obvious cardiovascular system tension. This appeared as the greater magnitude of tachycardia, metabolic disorders and is attended by high oxygen extraction. The paper shows it necessary to decide whether hemotransfusion should be made, by taking into account the compensatory capacities of the cardiovascular system, and not just hemoglobin levels.