Forty-two patients with both a current substance use disorder (SUD) and posttraumatic stress disorder (PTSD) were asked about the interrelationship of their two disorders, their treatment preferences and experiences, as well as possible deterrents to receiving PTSD treatment. Patients perceived their two disorders to be functionally related. They reported that when one disorder worsened, their other disorder was more likely to worsen; when one disorder improved, the other disorder similarly improved. Consistent with these perceptions, SUD-PTSD patients favored simultaneous treatment of their two disorders. The majority of SUD-PTSD patients were never referred to PTSD treatment. Although several possible deterrents to PTSD treatment were identified, only lack of trust appeared to differentiate PTSD treatment compliers versus noncompliers. Implications of these findings on referral and treatment practices are discussed.