Research indicates that many college students report posttraumatic stress disorder (PTSD) or substance use disorder (SUD), yet there has been scant attention paid to the co-occurrence of these disorders in college students. This review examines the co-occurrence of PTSD and SUD in college students. Recommendations for counseling centers are provided regarding the assessment of this population, an overview of treatment issues, and three areas of clinical importance when working with this population: risk behaviors, interpersonal violence, and social isolation. Future directions for research are also suggested. (Contains 1 table.)