The present study was designed to assess differences in dissociative symptoms in adults with Posttraumatic Stress Disorder (PTSD) vs. PTSD plus Disorders of Extreme Stress Not Otherwise Specified (DESNOS). This study was done for two reasons: (1) to better understand the clinical profile of DESNOS clients in order to inform more effective treatment, and (2) to further empirical research on the validity of the DESNOS construct. To assess severity of dissociative symptoms, the authors administered the Dissociative Experiences Scale (DES) to 155 participants with PTSD. Using the Structured Interview for Disorders of Extreme Stress (SIDES), participants were divided into two groups: those who also met criteria for DESNOS and those who did not. DES means are provided for the two groups. Participants with PTSD plus DESNOS scored higher than participants with only PTSD on the measure of dissociative symptomatology, particularly on the DES scales that tap absorption/fantasy and depersonalization/derealization. The two groups did not differ on the amnesia subscale of the DES. Findings support the construct validity of the DESNOS concept and further delineate the clinical profiles of community-based PTSD with and without DESNOS, thus contributing to the knowledge base on the assessment of complex adaptations to trauma.