Aim: This study was conducted in Turkish patients with polycystic ovary syndrome (PCOS) to determine the frequency of 4G/5G polymorphism genotypes of plasminogen activator inhibitor type-1 gene and to examine the role of this polymorphism in PCOS development. Materials and Methods: Genomic DNA obtained from 200 persons (100 patients with PCOS and 100 healthy controls) was used in the study. DNA was amplified by polymerase chain reaction using 4G and 5G allele-specific primers. Polymerase chain reaction products were assessed with charged-couple device camera after exposing to 2% agarose gel electrophoresis. Results: No statistically significant difference between the groups with respect to genotype distribution was found (p > 0.05) in the study. The 4G and 5G allele frequencies were indicated as 51.5% and 48.5% in patients, respectively, whereas this was 51%-49% in the control group. Conclusion: Consequently, it has been established by this study that the 4G/5G polymorphism genotypes of plasminogen activator inhibitor type-1 gene do not play a role in the development of PCOS in the Turkish population.