Peripheral blood lymphocytes of 18 normal controls and 32 patients with lymphoproliferative disorders were examined for the presence of surface markers. T cell frequency was decreased in chronic lymphocytic leukemia (CLL), Hodgkin’s disease and myeloma; and was normal or decreased in acute lymphocytic leukemia (ALL). Lymphocytes with surface membrane receptors specific for all Ig were markedly increased in lymphosarcoma and cryomacroglobulinemia, extremely decreased in ALL, normal in Hodgkin’s disease; only lymphocytes specific for IgM were increased in CLL. Receptors for C3 were diminished or absent in CLL and ALL. In the remission phase of ALL, EAC and E rosettes returned to normal and slg were almost normal. The approach presented in this article suggests a classification of these diseases in relation to the T and B cell frequency which may be useful for diagnostic and therapeutic implications