Several cognitive impairments related with conduct disorder (CD) severity have been reported. The present study attempted to determine the differences between groups of adolescent offenders (AO) with mild and severe CD and adolescent non-offenders (ANO) without CD. The sample was composed of 228 participants aged 12 to 16 years old, grouped in 117 AOs belonging to an education institution for young offenders (23 were classified as mild CD and 94 as severe CD) according to DSM-IV-TR symptoms) and 111 ANOs from regular education institutions. All participants live in the metropolitan area of Medellín city and belong to low socioeconomic strata. Statistical significant differences were found on verbal behavior tasks, when ANO and AO groups were compared. When the two groups of AOs were compared, the AO with severe CD exhibited significant lesser capacity of immediate verbal information recall and slower speed for color naming (p < 0.05). In our conclusions, findings that report significant lower verbal skills were confirmed, and very specific cognitive deficiencies in memory and verbal/visual speed processing were found in the AOs with severe CD group, which will oblige to design more rigorous experimental studies.