Polycystic ovary syndrome (PCOS) is a complex multi-factorial disorder involving a number of genetic and environmental factors. CYP1A1 (Cytochrome P450, family 1, subfamily A, polypeptide 1) gene, which belongs to Cytochrome P450 (CYP) super family, encodes a phase I cytochrome P450 enzyme, involved in the oxidative metabolism of estrogens. A recent study suggested that a common polymorphism Ile462Val of the CYP1A1 gene might be associated with PCOS development in Turkish women. To investigate a possible association between the CYP1A1 Ile462Val polymorphism and PCOS in Chinese women, we examined 205 PCOS patients and 177 healthy controls. All subjects were genotyped for CYP1A1. There was no statistical difference in CYP1A1 genotype and allele frequencies between PCOS cases and controls (chi(2) = 0.956, df = 2, P = 0.089 by genotype; chi(2) = 0.005, df = 1, P = 0.941 by allele). Compared with controls, there were no statistical difference in Val/Val genotype and Val allele frequency in the PCOS cases (4.9% vs. 5.1% by genotype; 51.7% vs. 52.0% by allele) (chi(2) = 0.009, df = 1, P = 0.926 by genotype; chi(2) = 0.005, df = 1, P = 0.941 by allele). Moreover, no association between CYP1A1 Ile462Val genotypes and metabolic parameters was observed in PCOS women. Our findings clearly indicated that this polymorphism does not represent an additional genetic risk factor for PCOS in Chinese women.