Aim. The aim of the study was the assessment of types and incidence of aggressive behaviours amongst psychiatric patients with violent acts marked in the referrals. Methods. 107 patients with aggressive or autoaggressive behaviours admitted to the General Hospital of Mental Disorders in Lubiaz and 37 controls without aggressive acts in referrals were examined. Two-way data analysis of the qualified individuals was performed. Firstly, the group was divided into 3 Subgroups depending on marked or not marked aggressive behaviours in referrals as well as violent acts reported during index admission. Subsequently the group was divided into 2 subgroups consisting of individuals with aggressive behaviours during hospitalization and patients without reported violent acts, both regardless of aggressive behaviours marked or not in the referrals. In each group, The Brief Psychiatric Rating Scale (BPRS) was used. The type, gravity and number of aggressive behaviours were assessed with the Overt Aggression Scale (OAS). Results. During the study, 34% of the participants presented aggressive behaviours. Over 80% of aggressive acts were observed during the first week of hospitalization. 84% of the patients with aggressive behaviours during index admission presented similar behaviours during previous hospitalizations. Conclusions The study corroborates the hypothesis that aggressive behaviours among patients admitted to the psychiatric hospital due to aggression are very frequent and predominantly observed in the early stages of hospitalizations. Identified important and predictive factors of possible aggressive behaviours are: violent acts marked in the referrals, treatment in the psy(sic)chiatric hospital without consent and aggressive behaviours during previous hospitalizations conformed in the medical reports.