In this study, we aimed to determine the gene polymorphisms of antioxidant enzymes that determine or affect antioxidant activity in the occurrence of the disease and/or complications during and after the surgery in patients who were decided to undergo coronary artery bypass surgery due to coronary artery disease. Blood samples taken before operation in 26 coronary artery patients who were decided to be operated according to the international procedure and the phenol/chloroform method was used to isolate DNA. DNA samples were amplified by using polymerase chain reaction (PCR) method with specific primers for MnSOD, CAT, GPx-3 antioxidant gene regions. As a result of the increasing process, the PCR products for the purpose of determining gene polymorphism, NGOMIV SMA f and BSA I restriction enzymes were used for MNSOD, CAT and GPx-3 gene region, respectively. Allele frequencies were determined and compared by Chi square test. VV (46.15%) and VA (53.85%) genotype for MnSOD region, i TT (22.22%), TC (16.67%) and CC (61.11%) genotype for CAT region, and CC (12.50%), TC (25%) and TT (62.50%) genotypes for GPx-3 region were obtained. While there was no statistically significant significance in terms of genotypes obtained in MnSOD and GPx-3 gene regions (P>0.05), a significant difference was found in the CAT gene region in terms of genotypes (P<0.01). Although oxidative stress is important in relation to cardiovascular diseases and postoperative complications, virtually no study of antioxidant enzymes in gene polymorphism are included in the literature. Work is lacking in relation to the subject.