Our purpose in this article is to review theories critically that have been used to explain immigrant women's health based on 4 case studies of Korean immigrant women's experiences in the United States and suggest directions for future development of theories on immigrant women's health. First, 3 existing theories on immigration and health (selective migration, negative effect of immigration, and acculturation) are concisely described. Then, the daily experiences of 4 low-income Korean immigrant women are described in a narrative mode, and the 3 existing theories are critiqued in terms of how they can explain the women's narratives. Finally, implications for future theory development on immigrant women's health experience are proposed based on the discussion.