It is wise to routinely assess delinquent youth for PTSD since adolescents that exhibit delinquent behavior are likely to have experienced maltreatment, which is a risk factor for PTSD. Assessment of PTSD among adolescents can be challenging. Developmental, psychological, and situational factors may impede the process of establishing rapport, which is necessary for productive assessment. It is important that the adolescent understands that the goal of assessment is to comprehensively understand as much as possible about his/her life experience including symptoms, behaviors, and thoughts. Interviewers should try to engender warmth through an egalitarian and friendly demeanor. Supporting the client’s sense of safety is an integral part of the assessment process. Youth with PTSD may suffer from other disorders such as conduct disorder and substance abuse. Multiple measures that use different formats and sources of information are recommended in assessing PTSD. These include evaluation of trauma exposure, PTSD interviews of children/adolescents, PTSD self-report measures, parental reports, and an evaluation of acute stress disorder, complex PTSD, and related problems. By understanding the clinical and scientific issues related to designing and conducting PTSD assessments, clinicians will be able to design useful multi-modal batteries for their work with delinquent adolescents. 4 tables, 70 references