A number of studies have reported that patients with schizophrenia have a higher body mass index (BMI) than the general population. Few Asian studies have examined BMI in patients with schizophrenia. The aims of the current study were to evaluate the distribution of BMI and prevalence of obesity in a large sample of Chinese patients with schizophrenia (n = 973) and to examine the sociodemographic and clinical correlates of overweight (BMI ≥ 25 kg/m) and obesity (BMI ≥ 30 kg/m). There was a preponderance of patients who were overweight (58.7%) and obese (73.6%) as compared with control subjects. Regression modeling of clinical and symptom factors in schizophrenia patients revealed that females were almost twice as likely to be obese compared with males and patients with comorbid medical conditions were more likely to be obese compared with those who did not have a comorbid medical condition (odds ratio, 1.6). Those prescribed typical antipsychotic medications were 1.7 times more likely to be obese, whereas individuals prescribed with both typical and atypical antipsychotic medications were 2.2 times more likely to be obese as compared with those prescribed atypical antipsychotics. A significant predictor interaction for obesity was observed between sex and typical antipsychotics, sex and comorbid medical conditions, and years of education and comorbid medical conditions. The higher prevalence of obesity in patients with schizophrenia is a matter of clinical and public health concern; interventions to reduce weight to healthy levels would result in both improved health and quality of life among patients with schizophrenia.