There is a high incidence of co-occurring disorders of PTSD and substance use. This presentation will consider what are the vulnerability factors that contribute to the development and maintenance of substance use disorders. It will examine the various treatment alternatives of sequential, parallel and integrated approaches. Various treatment approaches such as motivational interviewing, 12 Step programs and cognitive behavioral treatment approaches will be compared. The core tasks of psychotherapy will be highlighted including the critical role of the therapeutic alliance, psycho-education, collaborative goal-setting that nurtures hope, and various skills training, relapse prevention procedures that contribute to lasting changes. Examples of integrative treatment approaches will be presented.