Autoimmune haemolytic anaemia (AIHA) in infancy is rare. We report a case of AIHA in a male infant whose serum contained an antibody with apparent anti-Kpb specificity. Autoantibody with anti-Kpb specificity has been described in adults; to our knowledge, this is the first case of this kind described in infancy with AIHA. Clinical course and response to red cell transfusion are described.