Objectives: Increasing evidence suggests an association between inflammation and schizophrenia. The aim of this study was to evaluate vitamin B-12, 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 B-12, 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 B-12 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 B-12 levels. Increased inflammation may play a pathophysiological role in the development of atherosclerosis in schizophrenic patients.