Objective: One of the most important of mental health problems is care and management of psychiatric patients. In order to assess, effective factors on duration of stay on hospitalized patients a study has done in Razi psychiatric center.

Materials & Methods: This study has done in retrospective - descriptive way.

Results: The results of this study showed, there is no relationship between factors such as age, sex, place of birth and residence, occupational situation, source of reference and kind of treatment with length of stay in hospital. Moreover, this study suggested patients with schizophrenic disorders, had longer stay than patients with Mood Disorders and other mental disorders (P<0.05).

Conclusion: Besides, patients with previous recurrent admit, longer duration of illness, comorbidity (Physical or Mental) had longer stay (P<0.05). Single and divorced patients had longer stay than married patients (P<0.05) and patients under insurance policy stayed more time than other patients.