<p>An investigation was conducted with 1274 secondary school students to identify the incidence and elements surrounding self-harm among adolescents. The results showed: almost 20% average incidence; a ratio of self-harm of 2 to 1 of women compared to men; the use of multiple methods for self-harm; greater frequency in the modalities of cutting, scratching and hitting, as well as wrist and arm as the preferred areas of self-injury; high tolerance to pain and majority use of sharp objects in the situation of self-harm; negative emotionality and family situations as elements surrounding the realization of self-harm; activities linked to daily life after self-harm. The coincidence with national and international results and the requirements to deepen the phenomenon are discussed.</p>