Co-living or shared housing has become popular as an emerging housing option for young adults in many countries. Co-living allows residents to save rent by sharing common spaces such as a kitchen and living room in their home. In addition, co-living could provide a new opportunity for social relationship with housemates. Personal privacy is not fully ensured in shared housing so that social conflicts can occur among residents. However, co-living could improve the health of residents through social interactions with housemates. In this regard, this study examines whether co-living can improve physical and mental health of residents. This study explores the relationship between co-living and the health of residents based on the survey with a sample of 830 young adults in Seoul, South Korea. We compared the mental and physical health of house-shares with those of residents in general housing. There is no difference in the physical health between house-sharers and general people, but the mental health of house-sharers, specifically for the depression, is better than that of general people. The results imply that co-living could have the potential to improve the mental health of residents by providing the social relationship with housemates. The findings of this study could be a basis for developing an effective housing policy and planning for young adults.