Self-harm of the skin is a complex problem encountered mainly in adolescents and young adults. The aim of the study was to assess the prevalence of deliberate cutaneous self-harm without suicidal intent among secondary school teenagers of the Lodz region. A self-administered specially designed anonymous questionnaire was delivered to 1,448 secondary school teenagers, aged 12-19 years. The lifetime prevalence of self-reported deliberate self-harm was 19.5%, out of which 14.4% confirmed isolated cutaneous self-injury (self-cutting in the vast majority of cases), 1.7% ingested a substance or drug in excessive amounts and 3.5% declared both behaviours. Our results indicate that skin is the organ most commonly involved in deliberate self-harm. Dermatologists, especially those focussed on dermatosurgery and aesthetic dermatology, should understand the special issues relating to such patients before taking decisions concerning performing any procedures on these individuals, since deliberate self-harm has been recognised as one of the main risk factors of suicide.