This study has been performed on hypertensive patients in the Turkish population to determine the frequency of 4G/5G polymorphism genotypes of plasminogen activator inhibitor type-1 gene and with the aim of examining the role of this polymorphism in hypertension development. Genomic DNA obtained from 284 persons (176 patients with hypertension and 108 healthy controls) was used in the study. DNA was multiplied by polymerase chain reaction using 4G and 5G allele-specific primers. Polymerase chain reaction products were assessed by being exposed to 2% agarose gel electrophoresis. Results were evaluated with the chi-square test. The 4G allele frequency was 31.25% and the 5G allele frequency was 68.75% in patients, whereas it was 49/51% in a control group. 5G5G genotype was found statistically high (p < 0.001) in patients relative to controls. This study showed that the plasminogen activator inhibitor type-1 gene 4G/5G polymorphism and the 5G5G genotype appear to be associated with an elevated risk of developing hypertension in a representative sample of Turkish population.