The purpose of this study is to introduce LEM(Location Efficiency Mortgage) in U.S. and envision the affordable housing supply in the center of mass transit. Urban sprawl and increasing car-use have made commuting laborers set their financial condition back and have deteriorated city’s air condition. LEM is invented for the purpose of overcoming the urban sprawl problem and enhancing the purchasing power of low income house demander simultaneously. Owing to co-work of many institutes and authorities concerned, that is, The Natural Resources Defense Council, The Center for Neighborhood Technology, and The Surface Transportation Policy Project, the scheme of LEM has been made. Transit user who lives in location efficiency Area can borrow more money as much as transportation savings. This paper compares LEM with the various housing policies, such as Bogeumjari housing, SHIFT, and LIHTC. Also the limitations and controversy of LEM is described and the prospect and tasks of application LEM to Korean housing market is suggested.