The combination of discontinuous high-dose chlorambucil therapy with splenectomy greatly increased the prognosis of aggressive forms of chronic lymphocytic leukemia (CLL). The median survival for 43 patients was 84 months from diagnosis and 48 months from splenectomy. For 15 stages O, according to Rai classification, obtained after splenectomy, duration ranged from 3 to 105 months. The median survival of a group of patients showing "nodular splenic infiltration" was 104 months and superior to that of a group of patients showing "diffuse splenic infiltration" (72 months). In four of 15 cases studied, the peripheral blood lymphocytic clone disappeared after splenectomy.