This study assessed rates of imaginal exposure therapy (ET) utilization and completion of cognitive behavioral therapy (CBT) for posttraumatic stress disorder (PTSD) in a clinical setting and examined variables associated with CBT completion. Using a clinical definition, the completion rate of CBT was markedly lower than rates reported in randomized trials. CBT completion was inversely related to severity of overall pretreatment measures of PTSD, avoidance, hyperarousal, depression, impaired social functioning, and borderline personality disorder. Regression yielded avoidance and depression as unique predictors of completion. Most dropouts occurred before starting imaginal ET, although initiating ET was associated with greater likelihood of completion. Results highlight methodological differences between research and practice notions of treatment completion and the need for further study of variables influencing CBT completion in practice settings.