Since the 1990s there have been increasing concerns about coresident grandparents and their children in the U.S. This study focused on the coresident grandparents and grandchildren, categorized into 6 household structures, and examined whether household structure with sociodemographic variables affected economic well-being. The data from the University of Michigan Health and Retirement Study (HRS) were used, and frequencies, $x^2$ tests, ANOVA, and logistic regression analysis were conducted by SPSS Windows. The results of the study showed that there was a significant difference in the yearly household income among the 6 household structures. In addition, household structure affected the economic well-being. Especially, grandchildren in grandmother only, some parents present families, and in grandmother only, no parent families were more likely to be poor than those in both grandparents.