Adolescents are at high risk for violence exposure and initiation of drug use. Co-occurring substance use and trauma exposure are associated with increased risk of mental health disorders, school underachievement, and involvement with multiple systems of care. Coordination and integration of systems of care are of utmost importance for these vulnerable youth. This study delineates the negative sequelae and increased service utilization patterns of adolescents with a history of trauma, substance abuse, and co-occurring trauma and substance abuse to support the need for integrated mental health and substance abuse services for youth. Data from two national sources, the National Child Traumatic Stress Network and Center for Substance Abuse Treatment demonstrate the increased clinical severity (measured by reports of emotional and behavioral problems), dysfunction, and service utilization patterns for youth with co-occurring trauma exposure and substance abuse. We conclude with recommendations for an integrated system of care that includes trauma-informed mental health treatment and substance abuse services aimed at reducing the morbidity and relapse probability of this high-risk group.