Background: Schizophrenia is a mental illness with symptoms like delusions and hallucinations. A recent study concluded that individuals with vitamin D deficiency are twice more likely to have schizophrenia than optimum level vitamin D people. Objective: To measure schizophrenic patients` serum vitamin D concentration and compare it to healthy controls(non schizophrenics), and to investigate the relationship between serum schizophrenia and related potential risk factors. Subjects and Methods: Twenty patients with schizophrenia were recruited and compared to 20 controls with no major psychopathology using age and sex matched case control study. The SCID-1(semi-structured interview for making major DSM-IV Axis 1 diagnoses), was administered and the blood samples were withdrawn after patient consent on the same day. Results: Schizophrenic patients showed a significantly lower mean vitamin D level (14.8±4.5 IU) compared to control group (19.6±3.3 IU) (P<0.001). Higher vitamin D level participants were nearly 80% less likely to have schizophrenia compared to low level ones. Being older and female were 80%and 40% less likely to have schizophrenia respectively. Individuals with large body mass index were 1.2 times more likely to have schizophrenia compared to normal body weight. Smokers were 10% less likely to be schizophrenic compared to non-smoker participants. Conclusions: Patients with schizophrenia showed lower serum vitamin D level compared to healthy controls. Further studies are needed to explore the role of vitamin D in the pathogenesis of schizophrenia.