To verify that the rate of post operative infections is higher with homologous transfusion rather than without, 86 coronary artery bypass patient charts were retrospectively studied. Inclusion criteria were those of the autologous transfusion group. Four groups were defined : Gr 1 : No transfusion. Gr 2: Autotransfusion. Gr 3: Allotransfusion. Gr 4: Autotransfusion who also received homologous blood products. Although not significant, the bacterial infection rate was twofold higher in the Gr 3, than in the autologous group and was almost four times higher and significant (p < 0.01) when patients who received homologous blood products were compared to those who did not. These preliminary results lead us to enlarge our autotransfusion program and us encourage, to search for the cause of the decreased infection rate after autologous transfusion by prospective studies.