Objective : To estimate the annual economic costs attributable to cigarette smoking in Korea. Methods : The costs were classified as being direct medical and non-medical costs, indirect costs and others. We focused on those costs related that are incurred in the treatment of selected diseases (cardiovascular diseases, respiratory diseases, and cancers), which have been proven to be caused by smoking. In addition to the basic costs of treatment, the additional amount of costs occurred due to smoking was obtained by computing the population attributable risk (PAR%) caused by smoking. To compute the PAR%, relative risks of smoking to the number of outpatient visits, hospitalizations, and the death were estimated using the Cox proportional hazard model, respectively. Our major data source was the 'Korea Medical Insurance Corporation (KMIC) cohort study,' which was composed of a total of 115,682 male and 67,932 female beneficiaries who had complete records of their smoking histories in the year of 1992. Results : The annual costs that could be attributable to smoking were estimated to be in the range of 2,847,500 million Won to 3,959,100 million Won. The maximum estimate of 3,959,100 million Won includes 233,100 million Won for medical costs, 5,100 million Won for transportation costs, 27,600 million Won for care giver's economic costs, 69,100 million Won in productivity loss, 3,435,000 million Won lost because of premature death, 172,100 million Won in costs resulting from passive smoke inhalation and 17,100 million Won for costs that resulted from fires that were caused by careless smoking. Conclusion : Our study confirms that the magnitude of the economic burden of smoking to Korean society is substantial. Therefore, this study provides strong evidence that there is a strong need for a national policy of tobacco control in Korea.