CYP19 encodes aromatase, a key enzyme essential for estrogen biosynthesis. Single nucleotide polymorphism (SNP) rs2470152 in CYP19 is associated with serum estradiol (E2) level and the E2/T (estradiol/testosterone) ratio. A case‑control study including 661 individuals [364 polycystic ovary syndrome (PCOS) patients and 297 controls] was conducted to assess the association of SNP rs2470152 with PCOS. The subjects were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. Hormone levels were analyzed among various genotypes. The genotypic distributions of rs2470152 did not differ in PCOS patients when compared to the controls. However, differences in the E2/T ratio were detected, exhibiting a lower ratio in the heterozygous TC genotype in PCOS patients (p=0.01036) and controls (p=0.000). Testosterone levels also differed between the three genotypes of PCOS patients (p=0.00625), with a higher level in the TC genotype. Therefore, rs2470152 in CYP19 was not a major etiological factor for PCOS; however, the heterozygous TC genotype may inhibit aromatase activity, resulting in hyperandrogenism, particularly in PCOS patients.