The presence of the metabolic syndrome is an important risk factor for cardiovascular disease and diabetes. There are limited data on the prevalence of the metabolic syndrome in European patients suffering from schizophrenia. METHODS: All consecutive patients with schizophrenia at our university psychiatric hospital and affiliate services were entered in an extensive prospective metabolic study including an oral glucose tolerance test. The prevalence of the metabolic syndrome was assessed based on the National Cholesterol Education Program criteria (NCEP, Adult Treatment Protocol, ATP-III), adapted ATP-III criteria using a fasting glucose threshold of 100 mg/dl (AHA) and on the recently proposed criteria from the International Diabetes Federation (IDF). RESULTS: The analysis of 430 patients showed a prevalence of the metabolic syndrome of 28.4% (ATP-III), 32.3% (ATP-III A) and 36% (IDF), respectively. The prevalence of the metabolic syndrome in our sample of patients with schizophrenia is at least twice as high compared to an age-adjusted community sample in Belgium. CONCLUSION: The metabolic syndrome is highly prevalent among treated patients with schizophrenia. It represents an important risk for cardiovascular and metabolic disorders. Assessment of the presence and monitoring of the associated risks of the metabolic syndrome should be part of the clinical management of patients treated with antipsychotics.