The purpose of this paper is to contribute to the debate over agricultural trade and the environment by asking: Does a Japan-Korea FTA (JKFTA) increase nitrogen pollution from agriculture? In order to contribute to answering the above research question, we measure the potential impact of nitrogen pollution from agriculture caused by agricultural trade liberalization under the JKFTA, using the Global Trade Analysis Project (GTAP) model and the OECD Nitrogen Balance Database. The scenario we model assumes the complete removal of all import tariffs between Japan and Korea, not only in the agricultural sector but in non-agricultural sectors as well. The results show the JK-FTA is likely to lead to an overall increase in the total nitrogen surplus for Japan and Korea. Therefore, our results suggest that a JKFTA increases the potential nitrogen pollution from agriculture.