Population aging is expected to have a major impact on many aspects of social and economic life in the twenty-first century. The present study intends to investigate whether there are differences to take co-residence for the elderly with their children between Korea and the US. According to a theoretical argument from the mainstream about the living arrangements for the elderly, the theory argues that the living arrangements of the aged have resulted primarily from an increase in the resources of the aged, which has enabled increasing numbers of the elderly to afford independent living. The opposite argues that the decline of the multi-generational family occurred mainly because of increasing opportunities for the young and declining parental control over their children. Adopting the census data of the 1990s and the 2000s from the both countries, the present study found that both theories can be applied to the living arrangements for the elderly in Korea and the U.S. The present study concludes by suggesting some policy implications and future studies.