[ABSTRACT] Introduction: Prevalence of Conduct Disorder has been estimated between 4 to 10% . Objective: to estimate the prevalence CD in Colombian adolescents, using a rating scale by self report. Participants and Methods: 190 male adolescents from secondary school population, 12 to 16 year-old, were stratified and selected in a randomizing procedure, from Medellín - Colombia. A checklist including 14 diagnostic symptoms taken from the DSM-IV Criterion A for CD was constructed, with a scale of