This first known case of concurrent congenital dyserythropoietic anaemia (CDA) and autoimmune haemolytic anaemia (AIHA) which occurred in a hispanic male and spanned 6 years from the age of 2. Light and electron microscopy of bone marrow erythroblasts and immunophenotyping confirmed CDA; serum/eluate warm autoantibodies and positive direct antiglobulin tests (DAT) associated with severe, episodic anaemias established AIHA. Cytogenetic analysis of bone marrow cells and peripheral blood lymphocytes ascertained sex chromosome aneuploidy (48 XY,+ Y,+ Y). Recurrent, life-threatening episodes of transfusion-dependent anaemia refractory to steroids and intravenous immune globulin, were put into stable remission at age 8 years when splenectomy successfully managed both disorders.