The haematological findings resulting from the interaction of Hb A2 Indonesia trait with beta-thalassaemia trait and HbA2 Ind trait with Hb E trait are discussed. A person doubly heterozygous for Hb A2 Ind and beta-thalassaemia had mild haematological abnormalities essentially similar to those found in persons with beta-thalassaemia trait alone. A carrier for both Hb A2 Ind trait and Hb E trait had essentially normal haematological findings.