Follow-up of patients treated for severe trauma to the spleen, with autotransplantation (20 cases) or splenectomy (21 cases) included hepatic and splenic scintigraphy, intracutaneous skin testing with seven recall antigens and hematologic studies (red and white blood count, Howell-Jolly bodies, erythrocyte morphology, immunoglobulins, complements). In all reimplantation cases splenic tissue was scintigraphically demonstrated. After removal of the spleen due to severe traumatic ruptures the incidence of splenosis was 66%. Good clearance function in all reimplantation and splenosis cases was demonstrated by Howell-Jolly bodies and erythrocyte morphology. Autotransplantation of splenic tissue is a simple and safe procedure, without serious complications. As yet, however, there is no proof that it provides adequate resistance to infections. Reimplantation, therefore, should be performed only if spleen-preserving procedures are not feasible.