Haemoglobin Lepore-Hollandia is an extremely rare condition in which a small deletion gives rise to a deltabeta hybrid, beta-like globin. There are two single reports of patients from South Pacific Islands and Bangladesh. We describe a family from central Thailand, in which this Hb Lepore-Hollandia interacts with a common beta globin variant (beta(E) resulting from the codon 26, G-->A mutation) and alpha(+) thalassaemia (alpha(3.7)). This intriguing interaction caused a troublesome diagnosis, as the two proband brothers were diagnosed as having Hb E/beta thalassaemia. Molecular analysis of genomic DNA performed in this study allowed the definitive diagnosis of this complicated interaction. Such studies are required in the diagnosis of thalassaemia and haemoglobinopathies for particular regions like South-east Asia, where many different genotypes may give rise to haemoglobin disorders.