BACKGROUND: Inpatient smoking cessation programs have been known to be quite effective for smoking cessation, but it was rarely conducted among Koreans. This study was to investigate the effect of inpatient smoking cessation program among Korean smokers. METHODS: From March 1 to April 30, 2008, we carried out a randomized controlled trial for inpatient smoking cessation program among 70 smokers who were 18 years of age or over and admitted to a university hospital in Seoul, Korea. For the intervention group, a trained doctor conducted the systematic educational program for smoking cessation of 30 minutes to an hour. For the control group, they were advised with a 3-minute explanation for smoking cessation. We assessed the abstinence rates of study participants at 1 week, 1 month, and 3 months after discharge. RESULTS: In 3 months after the discharge, the abstinence rate for the intervention group was 37.1% while that of the control group was 14.3%. In simple logistic regression analysis, the smokers among the intervention group were 3.5 times more likely to abstain than those in the control group. After controlling for confounding factors, the smokers among the intervention group was 11.4 times more likely to abstain than those in the control group. CONCLUSION: For Korean smokers, the inpatient smoking cessation program showed a higher success rate of abstinence compared to simple advice and limited counselling.