In 2009, the National Council of Churches in Korea(NCCK) decided to hold the 10th WCC Assembly in Busan, Korea. In addition, leaders of Roman Catholic, WCC, and WEA met together and announced a joint document in 2011. After these events, there are many critical debates on interreligious dialogue of WCC and evangelicals are worrying about religious pluralism and syncretism which interreligious dialogue brings. People are now living in a rapidly changing postmodern society where religious pluralism dominates. As a result, they are challenged by postmodernism ideologies, pluralism, and inclusivism. It makes churches difficult to maintain their doctrinal convictions and faiths which they have persisted for the past centuries. Like this, pluralism is one of the greatest challenges. Evangelical churches, however, do not give a clear answer to those challenges. Thus, this paper attempts to answer how to response to the challenges, especially to the interreligious dialogue. For the purpose, the writer will try historical survey on numerous conferences and documents related to interreligious dialogue. Throughout the history, various conferences have dealt with interreligious dialogue and published written declarations. At the beginning, WCC started interreligious dialogue to solve the tensions between Christianity and other religions. However, they ignored the Bible and its teaching for their purpose. They developed nonbiblical ideologies and published many documents which support interreligious dialogue. It makes many theological and doctrinal differences between evangelicals and WCC. They have different views on the meaning and purpose of dialogue, week biblical basis, and some missiological errors. In addition, WCC is running to religious pluralism that all religions have an equal value for the salvation. Evangelicals should prepare to defend this kind of challenges, must go back to the Bible and its original teaching, and recover the power of the gospel. Furthermore, they need to change their attitude to other religions` people. To evangelize them without distorting God`s Word, evangelicals also need to study other religions. Although evangelicals do not accept interreligious dialogue which WCC insists, they need to establish biblical views which are based on the Bible, not the context or strategic needs of mission fields.