This present thesis has been prudently undertaken how to approach practically and theologically the ethical issues for the effective preaching with Confucian filial piety which has challenged Korean churches. Serious conflicts are arising among Korean families because of Confucianism teachings that filial piety is the highest virtue of all ethical teachings and that ancestor worship is the continuation of filial piety to the dead parents. This issue creates a rigorous religious controversy for Korean Christians and places obstacles in the path of evangelism in Korean society. Chapter one reveals the research orientation which gives general information on how to approach and develop this issue. I approach this issue historically, theologically, practically, and/or biblically. I adopt fundamental practical theology as the main research positioning, which was suggested by Don Browning. I also make use of seven movements proposed by J C Müller in order to present the literary research and six fundamental steps proposed by Lewis and Demarest only for the theological foundation in chapter three. Chapter two reveals the effect of Confucian ancestor worship has on Asian countries and Christians, specifically in China, Taiwan, Japan, and Korea, which are under the influence of Confucianism, and how Confucian ancestor worship hinders people from receiving and following Jesus Christ and a common barrier to evangelism in these Eastern Asian countries. Chapter three reveals the theological foundations of Confucianism and Christianity. Confucianism has its own specific theologies of worship form, temple, canon, afterlife, and gods like those of Christianity. A comparison with the theological foundations of Confucianism and Christianity is made for a better understanding of Confucian ancestor worship and filial piety. Chapter four reveals the differences between Confucian and biblical teachings on filial piety. Confucian filial piety was taught by Confucius who is a founder of Confucianism, while the origins of biblical filial piety are rooted in the Old and New Testaments. The Bible teaches that filial piety is directed toward living parents, but Confucianism teaches that filial piety is to both living and dead parents; filial piety to the dead parents is ancestor worship. Chapter five reveals the distinctions between Confucian and biblical teachings on ancestor worship. Confucians believe that dead ancestors are able to protect their own families, bring fortunes to their descendants, watch over their own families, and to reward the right and punish the wrong, but the Bible ascribes to ancestor worship as idolatry as taught in the second commandment. Chapter six reveals the ways of practical theological applications of filial piety and ancestor worship. I propose the ways of practical theological applications without compromise in the circumstance of the acceptance of ancestor worship as a custom. Further, I challenge preachers as central to reconciliation how to make an effort to aid the rooting of biblical filial piety into Korean society as a traditional Korean heritage. I hope that this thesis will help non-Christians to understand the Christian perspective of filial piety and ancestor worship and why Christians reject Confucian ancestor worship, and how Christianity emphasizes filial piety. Further, my intent is to help Christians confirm their beliefs, challenge non- Christians by showing what Christians believe, and give wisdom on how to create harmony with non-Christian family members.