We conduct an empirical analysis to examine the effectiveness of foreign exchange market interventions in Korea. Daily data of both actual and or alinterventions are constructed using information extracted from media articles and market reviews of the Korean Money Brokerage Corporation during the period from January 2000 to December 2018. We employ an event study approach to take into account the clustering feature of constructed intervention data. The event study is implemented by identifying intervention events from the intervention data, estimating their success rates, and verifying statistical significance of the success rates through a non parametric test. Our main findings are as follows. We find that interventions in the Korean foreign exchange market exert significant influence on the won/dollar exchange rate.Actual interventions are estimated to have greater influence than or alinterventions. Repeated interventions are found to be more effective tha none-time interventions.