Objectives: Increasing evidence suggests an association between inflammation and schizophrenia. The aim of this study was to evaluate vitamin B12, mean platelet volume (MPV) and red cell distribution width (RDW) levels in patients with schizophrenia. Materials and methods: Fifty-six patients diagnosed with schizophrenia and 30 age-and sex-matched controls were included in the study. Serum B12, MPV and RDW levels were measured in all patients. Results: RDW levels were significantly higher in patients with schizophrenia than in the controls (P< 0.001). MPV levels were increased in patients with schizophrenia; however, this increase was not statistically significant (P> 0.05). Serum B12 levels were significantly lower in patients with schizophrenia than controls (P< 0.001). Conclusions: Our results demonstrated that schizophrenic patients had high RDW and MPV levels along with decreased B12 levels. Increased inflammation may play a pathophysiological role in the development of atherosclerosis in schizophrenic patients.