Seventy-nine patients with chronic lymphocytic leukaemia were evaluated for the presence of autoimmune diseases and autoantibodies. One patient has polymyositis and two additional patients presented with features suggestive of pernicious anaemia and chronic active hepatitis. The Coombs' direct test was positive in 7% and immune thrombocytopenia was present in 8.1% of patients. Five (7%) patients had M-protein in the serum. No increased frequency of other autoantibodies was noted in our study group. We conclude that the propensity to develop antibodies is restricted only to the haematopoietic system and that there is no increased frequency of non-haematological autoimmune diseases in chronic lymphatic leukaemia.