The study deals with the immunological capacity and perfusion rate of splenic grafts in pigs after autologous transplantation into the omentum majus. 12 months after operation the weight and relative blood flow of the regenerated splenic tissue were clearly reduced. The number of antibody forming cells in the grafts was only slightly decreased compared to the normal spleen, whereas the autotransplants could balance a serum-IgM-deficiency, observed due to splenectomy, 4 months after grafting. Furthermore the mitogenic stimulation of T- and B-lymphocytes showed different proliferation rates for the autotransplants compared to the spleen.