This study investigates differences in terms of clinical and treatment management in psychiatric hospitalization associated to smoking ban. We collected data regarding medication, socio-demographic and admission characteristics from all patients admitted to an acute psychiatric hospital before and after a smoking ban was in force. We also assessed a limited sample of patients before and after the ban regarding nicotine dependence, motivation to quit smoking and attitudes towards the ban. More number of leaves of absence and movement restrictions during the ban period occurred in comparison to the pre-ban period. On the contrary a lack of significant differences in terms of hospital stay (duration, rate of voluntary admissions and voluntary discharges), use of sedatives and doses of antipsychotics was found. A period of adjustment regarding the deal with leave of access and facilitate nicotine replacement treatment may help future psychiatric facilities planning smoking free policies.