Hereditary persistence of fetal hemoglobin (HPFH), often associated with mutations in the beta-globin gene cluster, is normally benign, but a person carrying both HPFH and another beta-thalassemia (beta-thal) mutation will develop serious anemia. These people might be erroneously diagnosed as having homozygous beta-thal with common reverse dot-blot methods. Here we report a 5-year old boy with thalassemia intermedia, who is a compound heterozygote for the rare HPFH-6 deletion with codons 41/42 (-TCTT) beta(0)-thal, who inherited the deletion from his mother and the beta(41/42) mutation from his father.