The purpose of this study was to examine the course of comorbid posttraumatic stress disorder (PTSD) in 54 patients with another anxiety disorder. Using a prospective longitudinal design, the present study found that during the first 5 years of follow-up the probability of full remission from a chronic episode of PTSD was .18. Findings from this and other research confirm clinical impressions that a substantial number of people never fully remit from their PTSD even after many years. Variables associated with a longer time to remit from an episode of chronic PTSD were a history of alcohol abuse and a history of childhood trauma.