Background patients with schizophrenia may be at increased risk for diabetes mellitus Aims: to assess the frequency of diabetes in a population of French patients with schizophrenia Methods: The Positive and Negative Syndrome Scale (PANSS) was used to assess the psychotic symptomatology. All patients with schizophrenia or schizoaffective disorder according to the DSM-IV criteria, consecutively hospitalized in a psychiatric department or admitted in a day hospital for 2 years, were included in the study. Results : 114 patients were included in the study. The patients had a mean age of 35.2 years (SD=11.1), 70% were male, 30% were female. There were 92% Caucasian patients, 6% black, 2% Asian. Six per cent of the subjects (n=7) included in the study presented type 2 diabetes. Four patients received oral antidiabetic agents, including gliclazide (n=3), gliclazide and metformine combination (n=1). One patient received insulin. Two patients remained without treatment. The onset of diabetes occurred before the onset of atypical antipsychotics treatment for all patients. All patients with diabetes presented weight gain. The mean Body mass index was 29.9 kg/m2 (SD=6.5). Limitations: the fasting plasma levels of glucose were not systematically assessed in all patients included in the study. Conclusions : The frequency of diabetes mellitus in the present study is higher than in French general population (2-3%). However, the rate of diabetes is lower than in previous studies conducted in USA (10-15%). The frequency of diabetes, higher in US general population (6%), than in French general population could explain the differences.