This study was conducted to evaluate the effect of bupropion sustained-release (SR) on smoking cessation in patients with chronic posttraumatic stress disorder (PTSD). Fifteen veterans with chronic PTSD who desired to stop smoking enrolled in a 12-week double-blind evaluation of bupropion SR and placebo. Patients were randomly assigned in a 2:1 ratio to receive either bupropion SR or placebo. Bupropion SR was initiated at 150 mg daily for 3 or 4 days and increased to a final dose of 150 mg twice daily (300 mg daily total). Ten patients received bupropion SR and five received placebo. Nine of the patients who received bupropion SR were already being treated with at least one other psychotropic medication. One of the ten patients did not complete the study because of medication side effects. Eighty percent of patients receiving bupropion SR successfully stopped smoking by the end of week 2, and 6 (60%) of these 10 maintained smoking cessation at the study endpoint (week 12). At the 6-month follow-up, 40% of the patients (4 of 10) who received bupropion SR maintained smoking cessation. One (20%) of the five patients who received placebo stopped smoking and maintained smoking cessation at the 6-month follow-up. Bupropion SR was generally well-tolerated in combination with other psychotropic medications. Bupropion SR may be effective in helping patients who desire to quit smoking and who also have a concomitant anxiety disorder, such as PTSD.