Abstract: This study aims to measure Total Antioxidant Capacity (TAC) and Total Peroxides (TP) in schizophrenia patients with positive, negative and cognitive symptoms using Ferric Reducing Activity of Plasma (FRAP) and evaluate its relations with oxidative stress. We measured the plasma total antioxidant potential and total peroxides in 60 schizophrenia patients and in 60 well-matched non-schizophrenic control subjects. The association between the total antioxidative-oxidative potential and the symptoms, severity of schizophrenia were studied. Total antioxidant capacity/total peroxide of the clinical samples was measured using latest spectrophotometric measurement method. Results showed that plasma TAC was found to be lower in patients with schizophrenia than those of controls. On the contrary, the patients had high total plasma peroxide levels. Oxidative Stress Index (OSI) values of the patients were significantly higher than those of controls (p<0.001). Plasma TAC of each schizophrenia symptoms were significantly lower than healthy controls (p<0.01 for patients with negative and cognitive symptoms and p<0.001 for patients with positive symptoms). When intragroup comparisons were performed, patients with positive symptoms had significantly very low plasma TAC levels (p<0.001) compared to other negative (p<0.01) and cognitive subtypes (p<0.01). Plasma TAC in schizophrenia patients was significantly and inversely correlated with symptom severity. This study indicates that schizophrenia is associated with increased oxidative stress, depleted antioxidant status in schizophrenia subjects and supplementation with more antioxidative supplements could be considered in treatment.