Objectives:
The aim of the study was to assess the prevalence of self-injury among adolescents aged 16–19 years and to indicate demographic variable, selected environmental variables and risky behaviours coexisting with performing self-injuries by the respondents.

Methods:
The research encompassed 5,685 individuals, aged 16–19 years. During the research the Questionnaire designed by the authors was used.

Results:
Significant statistical differences were found between the number of adolescents performing self-injury and those who do not perform it, who use psychoactive agents, make suicide attempts, get drunk, run away from home, report conflicts with their parents, experience parental violence and peer violence and report alcohol addictions by family members.

Conclusions:
1. Self-injury is performed by 14% of adolescents aged 16–19 years, significantly more girls than boys. 2. Significantly more adolescents who perform self-injury, as compared to those who do not do it, use psychoactive substances, get drunk, report planning suicide, neglect school and more often consume alcohol. 3. Significantly more adolescents who perform self-injury, as compared to those who do not perform it, raised in a single parent family inform about alcohol addiction of a family member, conflicts with parents and the experienced psychological and physical violence experienced from their parents and peers. Significantly more girls who perform self-injury, as compared to those who do not perform it, experienced sexual abuse. 4. Performing self-injury by adolescents coexists with factors motivating to this type of behaviours: sense of helplessness, rejection, loneliness, sense of guilt, anger, impulsiveness, desire for revenge, school problems, conflicts with parents and peers.