Clinical manifestations of beta-thalassemia (beta-thal) intermedia phenotypes are influenced by the persistence of fetal hemoglobin (HbF) and by several polymorphisms located in the promoters of A- and beta-globin genes. The aim of this study was to evaluate the distribution of the -158Ggamma (C-->T) polymorphism and of the (AT)x(T)y configuration, as well as their eventual association with elevated levels of HbF in 188 beta-thal carriers and 229 wild-type individuals of Italian descent. The -158GgammaT and the (AT)9(T)5alleles were found to be associated with increased levels of HbF in beta-thal carriers, but not in wild-type subjects.