We describe two new missense mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene associated with chronic hemolytic anemia: mutation 1205C-->A in exon 10 predicts the amino acid change 402Thr-->Asn in the b-sheet M of the polypeptide chain, within the dimer interface (G6PD Covão do Lobo); mutation 1366G-->A in exon 12 predicts the amino acid substitution 456Asp-->His in the a-helix N, at the protein surface (G6PD Figueira da Foz).