It is well-established that autoantibodies against red cell membrane antigens, such as spectrin are present in plasma of humans and animals. It is shown here that antispectrin IgG antibodies can be eluted from the red cells of patients with beta-thalassaemia intermedia. It is suggested that these antibodies could play a part in the increased rate of destruction of red cells in homozygous beta-thalassemia, either by reacting with spectrin which is abnormally exposed on the red cell surface or by a cross-reaction with a different membrane component. No rise was found in serum antispectrin levels in beta-thalassaemia; anti-red cell membrane IgG levels were slightly raised, but there was considerable overlap between the levels in patients and in normals. No autoantibody could be found in eluates from cells of normal subjects or patients with sickle cell anaemia.