It is widely accepted by scholars of social policy that Korea needs to launch a research into the social security receipts and expenditure. It is in this regard that this paper studies the works of the leading international institutes such as ILO (International Labour Organization), OECD (Organization for Economic Co-operation and Development), EUROSTAT (Statistical Office of the European Community), and NOSOSCO (Nordic Social-Statistical Committee); how they define, classify and calculate the social security receipts and expenditure of their member countries. This paper also shows some similarities and differences amongst the social security statistics of these international institutes so that some useful implications to the Korean social security statistics can be properly exposed. This paper concludes that the social security statistics of Korea should be improved in accordance with the international standards.