A cross-sectional study was conducted to evaluate the relationship between sick building syndrome(SBS) and the environmental factors affecting SBS on 130 underground workers and 60 controls. The study consisted of 1) a review of environmental condition 2) measurement of temperature, O2, CO2, CO, and formaldehyde and 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using Indoor Air Quality questionnaire by National Institute for Occupational Safety and Health Bronchitis and dust allergy were more prevalent in underground workers significantly(p<0.05). Among the 18 symptoms related to the indoor air pollution, the experience rate of dry, itching or irritated eyes, sore or dry throat, chest tightness, tired or strained eyes and dry or itchy skin symptom is significantly different between the underground workers and controls. The diagnostic criteria of SBS was defined as at least one symptom is experienced 1-3 times a week during the last 1 month among 18 indoor air pollution related symptoms which can be relieved by moving out of the underground. Applying the criteria, the mean symptom score was significant higher in underground workers than controls significantly(p<0.05). These results indicated that underground workers are under inappropriate ergonomic and physical condition and inadequate ventilation. Their experience rate of symptoms related to indoor air pollution and prevalence of SBS was significantly higher than controls. To reduce the prevalence of SBS in underground workers, the surveillance system of indoor air quality, restriction of using fuel in underground and legislative regulations for the environment are needed to establish a better indoor air quality. Early detection, treatment and prevention of SBS through medical attention is also needed.