Splenectomized subjects show a higher incidence of myocardial ischemia and of Overwhelming Post-Splenectomy Infection (OPSI). It is doubtful that implanted splenic tissue guarantees an adequate protection from OPSI. The histological characteristics and the capacity of protection from OPSI of two models of omental autoimplantation of splenic tissue in rats were examined. The implanted splenic tissue offers a significant protection from pneumococcal sepsis, even though there is no relation between implant architecture and survival rate.