An association between thalassaemia and autoimmune haemolytic anaemia (AIHA) has not been previously recognized. 10 patients with thalassaemic diseases were found to give positive results to antiglobulin test with polyvalent antiserum. Tests with monovalent antisera revealed immunoglobulins on the red cells in all cases. From history of blood transfusion, auto-antibodies following alloimmunization were very unlikely. IgG, either alone or together with IgM or IgA, was the predominant antibody on the red cells. All cases had warm type AIHA and responded dramatically well with steroid treatment except 3 who eventually needed splenectomy which responded in 2 and failed in 1.