This study examined the comparative advantage of manmade textile (MMT) industries in the United States (US) and South Korea (SK). The Revealed Comparative Advantage (RCA) framework was used to assess the MMT industries’ performance in both countries from 2004 to 2013. With the recent ratification of the United States-South Korea Free Trade Agreement (KORUS FTA), it is important to understand the current state of these industries. Using UN Comtrade export data, the RCA index values were calculated and analyzed for 27 MMT commodities, three aggregate groups, and the whole industry. It was found that SK had a consistent comparative advantage for the whole industry. Furthermore, SK had a larger number of products with a comparative advantage. The research findings indicate that the MMT industry in SK is likely to outperform the US following the complete ratification of the KORUS FTA.