Objective: Catechol-O-methyltransferase (COMT), the product of the COMT gene, detoxifies the carcinogenic catechol estrogens. The aim of the present study was to examine the relationship between COMT Val158Met polymorphism and the risk of ovarian cancer.Material and Methods: The study groups consist of 94 individuals as a patients group with ovarian cancer (n=47) and control group (n=47). The allele and genotype frequencies were determined according to Hardy-Weinberg equilibrium (HWE). The allele and genotype frequencies. determined according to HWE. Genetic analysis were performed by real-time-polymerase chain reaction instrument, and the statistical analysis were performed by SPSS program.Results: Although no significant relationship was obtained among groups (p=0.413) regarding COMT gene Val158Met polymorphism, the genotype frequencies for COMT Val158Met (rs4860) polymorphism in groups was homozygote wild type GG genotype 25.5%, heterozygote GA genotype 46.8%, homozygote mutant AA genotype 27.7%.Conclusion: This study is the first to investigate the relationship between ovarian cancer and the Val158Met polymorphism in the COMT gene in a Turkish population. No statistically significant relationship was identified among genotypes belonging to the patient and control groups although sample sizes were relatively small and the analysis should be repeated in a larger cohort. (J Turk Ger Gynecol Assoc 2021; 22: 42-6)