Introduction:Use of varenicline for as long as necessary to achieve abstinence has not been studied. The aim of this study was to test whether smokers with mild-to-moderate chronic obstructive pulmonary disease (COPD) are able to quit if they use varenicline for a sufficient length of time.Methods:A total of 30 heavy smokers with COPD took varenicline for sufficiently long enough for smoking cessation. Smokers were allowed to smoke without a fixed quit date. The main endpoints were the time of voluntary abstinence (VA) and the continuous abstinence rate (CAR) at 12 and 18 months.Results:Of 28 subjects, eight subjects continued to smoke and 20 subjects stopped smoking, demonstrating a CAR up to 18 months (71%). Median time of treatment was 6 (range 3–24) and 2 (range 1–8) months for abstainers and non-abstainers, respectively, and the median time of VA for abstainers was 4 (range 1–21) months.Conclusions:Use of varenicline for more than the traditional 12 recommended weeks may be a good strategy to increase the cessation rate in heavy smokers with mild COPD.