A recent observation has shown that a common polymorphism in the alpha1-antichymotrypsin (ACT) confers a significant risk for Alzheimer's disease (AD). Furthermore, the apolipoprotein E epsilon4 allele (APOE*4) effect associated with AD risk is modified by the ACT polymorphisms. To evaluate the role of ACT polymorphism in AD, we conducted an association study of ACT polymorphisms in Chinese AD patients and normal controls. We found that the ACT polymorphism had no effect on the development of AD either alone or in combination with the APOE*4 allele.