Objectives. Following ischemia/reperfusion injury, antioxidant defense mechanisms may remain insufficient depending on the duration of ischemia which is caused by any reason (MI, after percutaneous coronary intervention, during cardiac surgery). After that, free oxygen radicals increasing within the cell cause structural deterioration. Cytokines which activate a series of reactions that cause tissue damage and inflammatory response are released during reperfusion of ischemic tissues. In this study, we aimed to compare the effects of dexmedetomidine and ketamine in cardiac ischemia/reperfusion injury.