Aim. The aim is to present selected aspects of imprisonment of people sentenced to two most severe terms of imprisonment: 25 years-sentence and life-sentence with special indication to imprisonment conditions and the most frequent mental health diseases. Material and method. A systematic review of psychological and penitentiary literature to find factors influencing prisoners’ mental health. Conclusions. Factors that influence mental health of long- -term prisoners are the same as the ones that influence prisoners' mental health, but last longer, cause many dysfunctional behaviours and may also negatively influence the aims and tasks of the prison penalty. Mental health of long-term prisoners has not been recognized yet. Resume. To help working with prisoners, especially those with long-term sentences, scientists should carry out professional research in that area.

Key words: mental health, prisoners sentenced.