Aim. The authors have made an effort to find the answer to the question what are the reasons for long hospitalizations in stationary wards and in the day hospital of the Wroclaw Mental Health Care Centre? In order to achieve this goal the correlation of the SCAN questionnaire diagnoses and length of stay in the aforementioned settings was analyzed. Methods. Analysis included 220 patients treated in the Wroclaw Mental Health Care Centre of which 111 patients were placed in day hospital and 109 in stationary wards. The correlation of length of stay in day hospital and in stationary wards with number of SCAN diagnoses in ICD-10 diagnostic groups was investigated. Results. Duration of hospitalization was relatively long for both day hospital patients (150 days) and stationary ward patients (58 days). Contrary to expectations there was no correlation between the number of SCAN diagnoses and length of stay in the hospital. Patients who were diagnosed using SCAN as having affective disorders and anxiety disorder stayed in the hospital shorter despite the fact they had more comorbid disorders than patients diagnosed using SCAN as having psychotic disorders both in day hospital and in stationary wards. Conclusions. Examination using the SCAN questionnaire cannot be used as prognosis of the length of stay either in day hospital or in stationary wards. Duration of hospitalization depends mainly on the diagnostic category (anxiety and affective disorders are associated with shorter hospital stays than psychotic disorders) irrespective of the number of diagnoses a patient received. It also depends on local therapeutic traditions and preferences (dominance of long-term care and the rehabilitation model of treatment instead of active acute intervention aiming at quick discharge from the hospital).