Deliberate self-harm (DSH) among adolescents is a high-risk condition for suicide. The aim of the present study is to describe the characteristic clinical features of adolescents with DSH according to our local context (Lisbon, Portugal), using easily available information from clinical settings. A case control study was constructed from a sample of 100 adolescents (aged 12 to 21 years). The sample was divided into two groups: adolescents with and without DSH. Case files were examined and data was completed by clinical interviews. Demographic, psychosocial, and psychopathological data were assessed and compared. Ninety-eight subjects completed the protocol. The DSH group was associated with the following: suicidal ideation or suicidal behavior as consultation motive, emergency room referral, previous follow-up attempts, suicidal ideation, psychosocial difficulties, or lack of therapeutic goals. There was a nonsignificant trend towards diagnosis of depression in the DSH group. These results reflect our clinical practice with adolescents and add data about teenagers who self-harm to the literature. Prevention and early recognition of DSH (and frequently associated depression) in adolescents are essential and could be life-saving measures. An integrated approach, which takes into account psychosocial difficulties, family dysfunction, and negative expectations, seems to be of great importance.