The spleen is a peripheral lymphatic organ where lymphocytes stop for long time during their circulation. We studied the peripheral blood lymphocyte subsets both in 30 subjects splenectomized for trauma and in 30 healthy, non splenectomized, subjects. The phenotypical characterization of lymphocyte subpopulations was performed employing monoclonal antibodies by direct immunofluorescence assays with single and double labelling. Comparing the results, we put in evidence, in splenectomized patients, an increase in all the lymphocyte subsets but one (L. G.L. Leu7+). The CD8+ population showed the major increase according with its large representation in the splenic tissue. Splenectomy induces a change in lymphocyte recirculating pool because of the loss of an important anatomical site of migration. This reduction of lymphocyte recirculating capacity can be related to a decreased efficiency in immunocompetence. In fact, many Authors showed that splenectomy is associated with several anomalies of both humoral and cellular immune response. In contrast with this, our group of splenectomized patients doesn't reveal a greater incidence of infections. We conclude that splenectomy realizes a new anatomical situation where the reduction of lymphocyte recirculating capacity can be related to a decreased statistical efficiency in immunocompetence.