To investigate the possible involvement of the transferrin (TF) gene polymorphism in the manifestation of Alzheimer's disease (AD), we analyzed the TF and apolipoprotein E (APOE) genotypes of 67 sporadic late-onset AD patients and 131 normal elderly controls in the Chinese population. Our data showed that the TF C1 homozygosity carriers had an increased risk of AD in subjects > or =75 years of age, showing that homozygosity for the TF C1 allele was associated with an approximately three-fold increased risk (OR=3.57, 95% CI, 1.24-10.27, P=0.014). No synergic effects were found between the APOE epsilon 4 allele and TF gene polymorphisms.