Several studies have reported the association of the SNP rs4077582 in the CYP11 gene with hyperandrogenism, which is one of the clinical manifestations of polycystic ovary syndrome (PCOS). These studies suggest that SNP rs4077582 may be involved in the etiopathogenisis of PCOS. To investigate whether the CYP11 gene SNP rs4077582 polymorphism is associated with the susceptibility to PCOS, we designed a case-controlled association study including 104 individuals. A case-controlled association study including 106 individuals (53 PCOS patients and 53 controls) was performed to assess the association of SNP rs4077582 with PCOS. Genotyping of SNP rs4077582 was conducted by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method that was performed on genomic DNA isolated from blood leucocytes. Results were analyzed in respect to clinical test results. The genotypic distributions of rs4077582 (CC, CT, TT) in the CYP11 gene in women with PCOS (CC, 29 (55.8%); CT, 20 (33.5%); and TT, 3 (5.8%). respectively) were significantly different from that in controls (CC, 44 (84.6%); CT, 6 (11.6%); and TT, 2 (3.8%) respectively) (P = 0.001). The allele frequencies in the PCOs women were: C, 78 (75%); and T, 26 (25%). This also was significantly different from the distribution in non-PCOs women: C, 94 (90.4%); and T, 10 (9.6%) (Table 2). In addition, rs4077582 C > T showed a association with PCOs by logistic regression analysis controlling for confounding factors. Our data suggest that SNP rs4077582 in the CYP11 gene is associated with susceptibility to PCOS.