The current article presents a review on psychiatric pathology in delinquent adolescents. The putative developmental significance of this co-occurrence is discussed within Moffitt's [Psychol. Rev. 100 (1993) 674] developmental framework on antisocial behavior. Articles on psychopathology in delinquent adolescents were retrieved through search engines (MEDLINE, Psychlit) and by exploration of references in those articles. Substantial evidence is at hand that delinquent adolescents have higher rates of externalizing and internalizing disorders when compared to adolescents in the general population. Although substantial limitations hamper interpretation of the findings, the marked similarities across a diversity of samples from different countries suggest that the findings are fairly generalizable. Evidence was found for differences in prevalence and developmental significance of psychiatric pathology between adolescent limited (AL) offenders and life-course persistent (LCP) offenders. Although psychopathology was more severe in LCP offenders, AL offenders still had significant and potential harmful levels of psychopathology. These findings emphasize the necessity of developing mental health services to delinquent adolescents and the necessity of adequate diagnostic and therapeutic interventions in these adolescents.