This document is based on mortgage securitization in Korea. The Korean mortgage market has changed rapidly since the financial crisis in December 1997. In the primary mortgage market, the competition between lenders has become intense; the proportion of long term mortgage loans has decreased; mortgage interest rates have dropped; and prepayments have increased. In the secondary mortgage market, the government enacted the Mortgage-Backed Securitization Company Act (MBS Company Act) and established Korea Mortgage Corporation (KoMoCo) in 1999. KoMoCo has issued Mortgage-Backed Securities (MBS) seven times, a total amount of 2.5 trillion Korean won as of December 2002. The purpose of this paper is to review the structural changes of the mortgage market and the institutional framework of mortgage securitization, to discuss policy issues for promoting mortgage securitization.