Background: We aimed to investigate the role of the physician in practice and the factors that influence the success rate of smoking cessation. Methods: This study retrospectively analyzed 126 adult smokers who had visited the outpatient department of pulmonology, and received motivational interviewing with or without supplement drugs. The findings include continuous smoking abstinence rate, which was evaluated at 6, 12 and 24 weeks, and the factors associated with continuous abstinence for 6 months or longer. Results: The patients with only motivational interviewing accounted for 57.9%, while the nicotine patch therapy was applied to 30.2%; and varenicline was prescribed to 11.9%. The smoking cessation success rates of at 6, 12, and 24 weeks were 55.6%, 47.6%, and 33.3%, respectively. However, even in the failure group at six months, tobacco consumption was decreased under 10 cigarettes per day in 42.1% (53/126). In multivariate logistic regression analysis, degree of Fagerst$ddot{o}$m Test for Nicotine Dependence (p=0.034; odds ratio, 3.607; 95% confidence interval [CI], 1.102-1.807), the absence of smoking-related lung disease (p=0.008; odds ratio, 4.693; 95% CI, 1.497-14.707), and education level (p=0.001; odds ratio, 181.420; 95% CI, 8.414-3,911.502) were the predictors of successful smoking cessation. Conclusion: An improved continuous smoking abstinence rate can be obtained by motivational interviewing, regardless of the association with pharmacotherapy.