(Purpose) The purpose of this study is to compare and analyze the policies on social integration of immigrants in Guro-gu in the ROK and in Shinjuku City in Japan, to identify the causes of similarities and differences between the two local governments’ policies of social integration of immigrants, and to seek to the improvement plan of integration policy of immigrants at the local governement level in Korea. (Research methods) This study was carried out based on literature review and field survey including official interviews of Guro-gu and Shinjuku city. These methods allow for researcher to find the background of policy development as well as specific and detailed programmes relating to social integration of immigrants in Guro-gu and in Shinjuku City. (Findings) Guro-gu and Shijuku City share many similarities such as autonomus region of national capital city, more than 10% immigrant background population, programmes composed of language education, counseling for immigrants, multi-langual information etc. However, there are distinct differences between the two in their management systems of policies: The prime action office is welfare-related department in Guro-gu, while it is regional development-related department in Shinjuku City. The buget for policies is composed of expenditures from National government, Metropolitan government(Seoul Metropolitan City), and local autonomous government(Guro-gu) in Guro-gu, while it is 100% expenditure of Shinjuku City. (Conclusion and recommendations) The Republic of Korea and Japan have both similarities and differences in the policy environment on social integration of immigrants. It is desirable for Korean local government to understand Japanese cases to derive useful ideas for development of Korean policy at the local level.