This project working paper discusses the prevailing system of income security for older persons in the Republic of Korea with regards to coverage, beneficiaries, and sustainability. It also discusses recently undertaken reforms of the income security system with regards to their budgetary implications. After the introduction of a mandatory pension scheme, coverage of pensions increased rapidly in the Republic of Korea. However, as the pension system in the Republic of Korea was introduced relatively late, poverty of older persons is still high. The paper concludes that recent reforms may be able to address the high poverty rate of older persons in the Republic of Korea. Further reforms may be required with regards to the Government employees pension scheme to ensure its sustainability.