A pilot study was conducted to investigate the feasibility and effectiveness of behavioral activation (BA) therapy for veterans with posttraumatic stress disorder (PTSD). Eleven veterans seeking treatment at a Veterans Administration outpatient PTSD clinic were enrolled in the study protocol, consisting of 16-weekly individual sessions of BA. Nine veterans completed the protocol, one participant completed 15 sessions, and one dropped out after one session. Clinician-rated PTSD symptom severity showed significant pre- to posttreatment improvement and was associated with a moderate effect size. A number of participants also were improved on measures of depression and quality of life, but changes did not reach statistical significance. Findings suggest that BA is a well-tolerated, potentially beneficial intervention for veterans with chronic symptoms of PTSD.