Even though psychiatric problems are commonly observed in patients attending emergency departments (ED), to our knowledge, there are no studies about the prevalence of mental disorders in patients admitted to ED wards. In the present study we evaluated the psychiatric disorder morbidity in patients admitted to ED wards for physical problems. General Health Questionnaire‐30 (GHQ‐30) was submitted to 556 patients admitted to the ED ward. All GHQ‐30 positive (score > 4) and one third (randomly selected) of the GHQ‐30 negative (score < 5) patients underwent the Mini International Neuropsychiatric Interview (MINI‐IV), a structured interview to diagnose mental disorders according to DSM‐IV criteria. Patients with positive and negative scores to GHQ‐30 were 293 (52.7 per cent) and 263 (47.3 per cent) respectively. A total of 351 patients underwent the MINI‐IV. In the total sample the extrapolated prevalence was 44.4 per cent for all mental disorders, 21.7 per cent for Anxiety Disorders, 10.2 per cent for Depressive Disorders, 9.7 per cent for Adjustment Disorders and 3.2 per cent for Alcohol Dependence. In only 53 patients (9.8 per cent) the diagnoses at discharge was a mental disorder and in 32 patients (5.7 per cent) a psychiatric consultation was requested. In conclusion, a high rate of Anxiety and Depressive Disorders was found in patients admitted to the ED ward, but in most of these patients the mental disorders were not recognized by the emergency physicians. Copyright © 2001 John Wiley & Sons, Ltd.