Koreans began to undertake the conservation of their art and architectural artifacts approximately fifty years ago after modern concept of conservation were introduced by japanese during the Japanese Colonial Period(1910-1945). But still the modern concept of conservation is not clear to many Korean conservators because they have been concerned about conservation techniques to recover the original from of the remains be destroyed. Also, Korean conservation practice has neglected the philosophical issues and ethics of conservation. So, in this article, I described various terms referring to 'conservation' which have been used in western countries, Japan, China, and Korea, and compared their similarities and differences to have more clear idea on the modern concept of conservation. In the next chapter, I summarized several theoretical issues which had been discussed among western conservators over the centuries. Specially, I described closely the modern issues and ethics which have been presented in the twentieth century. As many conservation projects in Korea have resulted unsatisfactorily or been suspended altogether, because lacking a coherent theoretical dialogue on conservation and discussing an ethical issues of conservation. Therefore, I believe that more vigorous dialogue on these issues in Korea may lead conservators to consider their tasks in a more productive light, and the Korean artifacts may preserve well.