Recent studies have provided evidence toward the possible involvement of brain cholesterol homeostasis in late-onset Alzheimer's disease (LOAD). We analyzed an intronic T-->C substitution (rs 754203) of the cholesterol 24S-hydroxylase (CYP46) gene, encoding an enzyme acting on brain cholesterol turnover, which has been recently associated with an increased risk of AD, dependent or not on Apolipoprotein E (ApoE) genotype. No significant association was found for the CYP46 polymorphism in LOAD compared to the controls, even after stratification for the presence/absence of the ApoE*4 allele. Our data do not support a role of the CYP46 polymorphism as a possible susceptibility factor for developing AD.