OBJECTIVES The symptoms of fungal infections vary from minor to severe. According to recent reports, fungal infection prevalence is increasing due to increases in the aging population and in patients with compromised immune systems. However, the total prevalence of fungal infections in South Korea is unknown. We investigated the recent 5-year prevalence of each type of fungal infection in South Korea across age, sex, and regional groups. METHODS Nationwide data from the National Health Insurance of South Korea were used. The target population included patients who had received treatment for a fungal infection that was listed as the main disease. For each patient, multiple treatments were counted as one case per year in the data analysis. RESULTS The annual prevalence of all-type mycoses increased from 6.9% in 2009 to 7.4% in 2013. Among the specific groups, the prevalence of dermatophytosis was highest (5.2%), followed by that of opportunistic mycoses (1.7%) and superficial mycoses (0.2%). The prevalence of subcutaneous mycoses and generalized mycoses was very low (8 cases per 100,000 persons and 3 cases per 1 million persons, respectively). CONCLUSIONS Every year, approximately 7.1% of the Korean population receives treatment for fungal diseases. Cases of opportunistic mycoses are assumed to increase each year. Therefore, further research is needed to understand and monitor the prevalence of mycoses to establish management policies to reduce the burden of fungal diseases.