The aim of this review article is to present current knowledge of self-mutilation among adolescents as a phenomenon and to define what kind of knowledge is lacking based on existing literature. The literature searches were executed in the CINAHL and Medline databases in 2010. The analysed data consisted of 126 articles and inductive content analysis was carried out. Existing knowledge of self-mutilation was categorized into the following two classes: (1) self-mutilation as a phenomenon and (2) caring for persons who self-mutilate or self-harm.