Background. Penitentiary institutions are particularly liable to the emergence and spreading of detrimental social phenomena. Compulsory stay in a closed institution and the necessity to adjust to conditions dramatically different from those of the prisoner’s former life are often a source of frustration. Self-aggression in prisons usually takes the form of self-injury. Self-mutilation is often a ticket to being promoted in the prison subculture pecking order, or a way to enforce some earlier unattainable demands. Frequently it may be also the prisoner’s response to deprivation of his basic needs. Material and methods. The anonymous study was conducted on the premises of Prison No. 2 in Lodz, between December 2006 and March 2007...