Since the hospital treatment has the influence on the reduction of quality of life of mentally ill patients, the intention of contemporary psychiatric management would be to provide appropriate psychiatric assistance and to reduce hospital treatment as much as possible. Current treatment of mentally ill in Serbia is conducted in conditions of insufficiently developed community psychiatric treatment. Therefore, the aim of this research was to investigate the causes which led to extended treatment of in hospital patients on ‘Acute psychoses department of Special psychiatric clinic’, which is one among the five biggest psychiatric hospitals in Serbia. Duration of in hospital treatment was analyzed in 298 female patients who were consecutively admitted to the department within one year period, with regard to clinical, demographic, social and economical factors. Obtained results show that among the type and severity of disease, the critical role of extension of in hospital treatment play, some demographic, social and economic factors as well. Results gained were discussed in detail during the research.