Objective: College matriculation begins a period of transition into adulthood, one that is marked by new freedoms and responsibilities. This transition also is marked by an escalation in heavy drinking and other drug use as well as a variety of use-related negative consequences. Trauma and symptoms of posttraumatic stress disorder (PTSD) may affect alcohol and drug problems and, thus, may be a point of intervention. Yet, no studies have examined trauma, PTSD, and alcohol and drug problem associations during this developmental period. The present study provides such an examination. Method: Matriculating college students (N = 997) completed surveys in September (Time 1) and at 5 subsequent time points (Time 2-Time 6) over their 1st year of college. With latent growth analysis, trajectories of alcohol- and drug-related consequences were modeled to examine how trauma (No Criterion A Trauma, Criterion A Only, No PTSD Symptoms) and PTSD (partial or full) symptom status predicted these trajectories. Results: Results showed substantial risk for alcohol- and other drug-related negative consequences that is conferred by the presence of PTSD at matriculation. Those with both partial and full PTSD started the year with more alcohol and drug consequences. These individuals showed a steeper decrease in consequences in the 1st semester, which leveled off as the year progressed. Both alcohol and drug consequences remained higher for those in the PTSD group throughout the academic year. Hyperarousal symptoms showed unique effects on substance consequence trajectories. Risk patterns were consistent for both partial and full PTSD symptom presentations. Trajectories did not vary by gender. Conclusions: Interventions that offer support and resources to students entering college with PTSD may help to ameliorate problem substance use and may ultimately facilitate a stronger transition into college and beyond. (Contains 1 footnote, 1 table, and 4 figures.)