[en] Objective: To assess the diagnostic properties of 2 different screening guidelines for the detection of diabetes in patients diagnosed with schizophrenia. Method: Over a 2-year period (November 2003-November 2005), 415 patients with schizophrenia were screened with a full laboratory screening and a 75-g oral glucose tolerance test (OGTT). The sensitivity of 2 screening strategies was compared with the "gold standard": the OGTT. The 2 strategies were (1) assessing fasting glucose in all patients, as suggested by the American Psychiatric Association/American Diabetes Association (APA/ADA), and (2) a screening strategy derived from the guidelines of the World Health Organization of assessing fasting glucose in all patients (step 1) and subsequently performing an OGTT in patients with impaired fasting glucose (step 2). Results: Of the total sample, 6.3% (N = 26) met criteria for diabetes, resulting in a mean annual incidence of diabetes of 3.15% (6.3% incident cases/2 years). A screening based on the APA/ADA guidelines detected diabetes in 12 (46.2%) of the 26 cases identified by the OGTT. The proposed 2-step strategy detected 25 (96.2%) of 26 cases. Conclusion: The data suggest a high incidence of diabetes in patients diagnosed with schizophrenia. However, the guidelines to detect diabetes as proposed by the APA/ADA did not sufficiently detect diabetes in this specific high-risk group. The alternative 2-step strategy was able to detect the vast majority of diabetes cases and should therefore be considered in the clinical routine of screening and monitoring patients with schizophrenia.