Platelet and leukocyte counts and leukocytotoxic and platelet antibodies were studied in 32 patients with autoimmune hemolytic anemia (AHA). Leukopenia was present in 59.4%, thrombocytopenia in 59.4% and leuko-thrombocytopenia in 40.5% of the cases. Specific antibodies for granulocytes were found in 81.3%, platelet antibodies in 90.6%. The AHA, leukopenia and thrombocytopenia generally presented a dissociated evolution and a different response to immunosuppressive treatment. The leukopenia of 2 and the thrombocytopenia of 6 patients appeared at variable time intervals after the AHA or the detection of leukocyte and platelet antibodies. Thrombocytopenic purpura was present in 6 patients, and in 2 of these since infancy. AHA may thus be a comples autoimmune syndrome that may involve leukocytes and platelets as well as erythrocytes, with synthesis of autoantibodies specific for different blood cells.