OBJECTIVE: Complexity of schizoaffective disorder makes the identification of its pathophysiology a great challenge and there are very limited published data about the role of oxidative stress. Oxidative DNA damage has not been investigated in schizoaffective disorder. Therefore, we aimed to evaluate oxidative DNA damage together with oxidative stress and urotensin-II in patients with schizoaffective disorder. METHODS: Fifty-four patients who were diagnosed as schizoaffective disorder bipolar type (27 of them were in symptomatic remission and 27 of them were not) and 27 healthy volunteers were included in the study. Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), and urotensin-II (U-II) levels were calculated and evaluated. RESULTS: TAS and U-II levels were found to be lower in the patient group with and without remission when compared with the control group separately. There were no significant difference in terms of TOS, OSI, and 8-OHdG. Similar results were obtained when those in symptomatic remission and non-remission patient groups were combined and compared with the control group. CONCLUSION: TAS levels in schizoaffective disorder patients were lower than controls, which may mean a vulnerability to the oxidative stress but there were no differences in terms of oxidative DNA damage. U-II levels in schizoaffective disorder patients were significantly lower than controls in contrast with our previous study.