BACKGROUND: The prevalence of tuberculosis is closely related to socioeconomic status. Although the nationwide prevalence of pulmonary tuberculosis was constantly decreasing during past 30years, there were few studies about prevalence of specific social groups in Korea. We examined prevalence of pulmonary tuberculosis among university freshmen, which might represent one of the specific social groups in Korea. METHODS: The prevalence of radiologically active pulmonary tuberculosis among Seoul National University(SNU) freshmen was investigated from 1988 to 1997. And those results were compared with prevalence data of SNU freshmen from 1977 to 1987 and also with prevalence of age matched general population. RESULTS: There was continuous decrement of prevalence of pulmonary tuberculosis among university freshmen. In 1985 and 1990, there was significant prevalence difference between university freshmen and general population. But in 1995, the prevalence of both groups was not significantly different. CONCLUSION: The prevalence of pulmonary tuberculosis in university freshmen has decreased steadily. The prevalence of pulmonary tuberculosis in university freshmen was lower than that of age-matched general population during past 20years. However, this trend was not evident in 1995.