This study uses the developmental migration paradigm developed by Litwak and Longino (1987) as a framework to investigate the health and social determinants of late-life elderly mobility to retirement communities. Data from four waves of the Longitudinal Study of Aging are used to predict the likelihood of moving from the general community to two types of retirement communities--those with group meals and those without group meals. Multinomial logistic regression reveals that the likelihood of migrating to both types of retirement communities increases as disability advances to moderate levels, but declines as disability becomes severe. Migration to retirement communities is also more likely among elderly persons who live alone and among those whose children do not live nearby. The results suggest that retirement community migration in middle and late old age is motivated not only by social and amenity considerations, but also by the need for assisted living arising from physical frailty. Implications for developmental migration theory and long-term care policy are discussed.