This study investigated the interrelations among mental health problems, posttraumatic stress disorder (PTSD), age, ethnicity, gender, and recidivism over a three-year period in a sample of 417 male and 170 female juvenile offenders. At the time of first admission to a juvenile detention center, boys reported higher alcohol/drug use, whereas girls reported greater anger/irritability. Caucasian offenders evidenced higher rates of alcohol/drug use and somatic complaints than African American offenders. Younger age was related to higher levels of anger/irritability and depression/anxiety, although older adolescents with PTSD reported the highest levels of alcohol/drug use, anger/irritability, somatic complaints, and depression/anxiety. Across multiple admissions to detention, alcohol/drug use increased for all youth, whereas somatic complaints decreased for boys only. Younger offenders were more likely to recidivate than older offenders; however, girls and younger African American youth with PTSD were more likely to reoffend than were their peers.