Background: Asthma is one of the most common chronic condition. However, there have been no studies to examine current asthma prevalence trends in Korea through the analysis of nationwide surveys. Patients and Methods: Data was acquired from aged 20-59 years who participated in the First Korean National Health and Nutritional Examination Surveys (KNHANES), which was conducted in 1998, and the second year of the Fourth KNHANES, which was conducted in 2008. To estimate the prevalence with age and gender standardization, we used data from the Population and Housing Census, which was conducted by Statistics Korea in 2005. Results: The prevalence of physician-diagnosed asthma increased from 1998 to 2008 (1998: 0.7%, 2008: 2.2%). The prevalence of asthma medication usage also increased from 1998 to 2008 (1998: 0.4%, 2008: 0.8%), however, the prevalence of wheezing decreased between 1998 and 2008 (1998: 13.5%, 2008: 6.36%). A similar trend was observed after estimating with age and gender standardisation. Allergic rhinitis might be the reason for the increased prevalence of physician-diagnosed asthma, while the observed decrease in wheezing could be related with the decrease in smoking or the increase in the use of asthma medication. Conclusions: The present study showed that the prevalence of both physician-diagnosed asthma and asthma medication usage increased from 1998 and to in Korea, despite the changing pattern in diagnosing asthma.