Burak Kulaksizoglu,1 Sibel Kulaksizoglu2 1Psychiatry Department, Antalya Education and Research Hospital, 2Biochemistry Department, Antalya Education and Research Hospital, Antalya, Turkey Introduction: The aim of our study was to evaluate the relationship between neutrophil/lymphocyte ratio (NLR) and total antioxidant status (TAS), total oxidative status (TOS), oxidative stress index (OSI), paraoxonase, and total thiol (T.thl) in schizophrenic patients compared to healthy control group and investigate the relationship between these parameters and psychopathological symptoms.Methods: The study population consisted of 61 healthy control subjects and 64 volunteer patients monitored in the outpatient clinics of psychiatry of Antalya Education and Research Hospital. Hemograms were determined by using a fully automated hematology analyzer (Beckman Coulter LH780). Serum TOS, TAS, paraoxonase, and T.thl were measured using a novel automated colorimetric measurement method developed by Erel. Sociodemographic data forms were completed by the participants. The Positive and Negative Syndrome Scale (PANSS) was used to assess the patients.Results: Neutrophils, NLR, TAS, and TOS significantly increased, whereas lymphocytes, T.thl, and T.thl/OSI ratio were significantly lower in the schizophrenia patient group compared to the control group. A statistically significant positive relationship was found between PANSS positive subscale with leukocytes and significantly negative relationships were found between PANSS positive subscale with lymphocytes and T.thl/OSI ratio. Significant positive relationships were found between PANSS total subscale with leukocytes and NLR. Statistically significant negative relationships were found between PANSS total subscale with lympho­cytes and T.thl/OSI ratio. In the group of patients with schizophrenia, a significant negative correlation was found between NLR with T.thl/OSI. In the group of patients with schizophrenia, a significant positive correlation was found between NLR with TOS and OSI.Conclusion: By measuring NLR, which is simple, inexpensive, and suitable for routine use, we can obtain information about oxidative stress and psychopathological symptoms in patients with schizophrenia. Inflammation and oxidative stress are important in the pathogenesis of schizophrenia and are closely related with the patients’ clinical symptoms. Keywords: oxidative stress, antioxidant status, PANSS, schizophrenia