Aggressiveness is a frequent and problematic aspect of the treatment of forensic patients. This study examines the correlation of aggressiveness and its subtypes with quality of life enjoyment and satisfaction, personality dimensions and family functioning. The research is conducted on 99 psychiatric patients diagnosed with schizophrenia or psychotic disorder similar to schizophrenia (F20-F29) in two forensic psychiatry institutions. The patients committed criminal offence in state of insanity. These offences had signs of aggressive acts and the patients were therefore admitted to inpatient psychiatric forensic institutions. The research was conducted by using the Aggressiveness Questionnaire (AG-87), the Eysenck Personality Questionnaire, the Quality of Life Enjoyment and Satisfaction Questionnaire and the Family Functioning Scale. The results show that aggressiveness has a negative correlation with the quality of life enjoyment and satisfaction. Regression analyses indicate that bad family relations and psychoticism are significant predictors of aggressiveness and its subtypes. We can conclude that forensic patients who committed aggressive offence in psychotic state, who at the same time score higher values on psychoticism scale and report negative family relations, are more likely to express aggressiveness also during their stay in forensic psychiatric hospital.