OBJECTIVE: To evaluate a pilot 4-day residential smoking treatment program for smokers who had relapsed after participation in an outpatient smoking program. DESIGN: A single-arm clinical trial. Participants stayed in a supportive, smoke-free environment for 4 days during which they attended educational sessions on nutrition, exercise, and psychology. Nicotine withdrawal was treated with nicotine inhalers and patches. After discharge, participants attended monthly outpatient group sessions for 6 months. SETTING: The Durham, NC Veterans Affairs Medical Center residential unit. PARTICIPANTS: Twenty-three medical outpatient smokers. MEASUREMENTS: Seven-day point prevalence smoking abstinence was determined by self-report of zero cigarettes smoked and verified by exhaled carbon monoxide <8 parts per million. MAIN RESULTS: Participants' mean age was 57.4 years; 100% were male; 61% were Caucasian; and 39% were African American. The mean score on the Fagerström Test for Nicotine Dependence was 7.1 (SD 2.3). Daily nicotine doses ranged from the nicotine inhaler alone to 56 mg of transdermal nicotine plus nicotine inhaler. Verified smoking abstinence on discharge (after 4 days) was 21/23 or 91.3% (95% confidence interval [95% CI], 73 to 100). At 6 months, the 7-day point abstinence rate was 6/23 or 26.1% (95% CI, 15 to 36). CONCLUSIONS: This pilot residential smoking treatment program was designed to assist smokers who relapsed after outpatient treatment. Four days of residential smoking therapy successfully relieved smoking withdrawal. At 6 months after discharge, participants maintained an abstinence rate comparable to other medical therapies for smoking.