In some countries with high smoking prevalence, smoke-free legislation has only been implemented in specific public places, as opposed to a comprehensive ban on smoking in all public places. The purpose of this study was to provide valid data on second-hand smoke (SHS) exposure that reflect the consequences of incomplete smoke-free legislation, and provide a rationale for expanding this legislation.Indoor and outdoor environmental exposure (fine particulate matter [PM2.5], air nicotine, and dust 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [NNK]) was monitored in 35 public places where smoking is prohibited by law in Goyang, Republic of Korea. Biomarkers of SHS exposure (urinary cotinine, hair nicotine, and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) were measured in 37 non-smoking employees. Geometric means and standard deviations were used in comparison of each measure.Considerable exposure of SHS was detected at all indoor monitoring sites (PM2.5, 95.5 μg/m(3) in private educational institutions; air nicotine, 0.77 μg/m(3) in large buildings; and dust NNK, 160.3 pg/mg in large buildings); environmental measures were higher in private or closed locations, such as restrooms. Outdoor measures of SHS exposure were lowest in nurseries and highest in government buildings. Biochemical measures revealed a pattern of SHS exposure by monitoring site, and were highest in private educational institutions.The evidence of SHS exposure in legislative smoke-free places in Korea suggests that incomplete smoke free legislation and lack of enforcement of it might not protect people from exposure to smoke. Therefore, active steps should be taken toward a comprehensive ban on smoking in all public places and its enforcement.