Individual differences in the quality of early experiences with primary caregivers have been reliably implicated in the development of socioemotional adjustment and, more recently, physical health. However, few studies have examined the development of such associations with physical health into the adult years. To that end, the current study used prospective, longitudinal data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (N = 1,306, 52% male, 77% White/non-Hispanic) to investigate whether associations between direct observations of maternal sensitivity in the first 3 years of life and repeated assessments of two commonly used, objective indicators of physical health (i.e., body mass and mean arterial blood pressure) remained stable or diminished in magnitude over time. Associations between early maternal sensitivity and lower body mass remained relatively stable from age 54 months to 26 years and were robust to the modeling of autoregressive and second-order stability processes as well as the inclusion of potential demographic confounders. In contrast, although associations between early caregiving and lower mean arterial pressure remained relatively stable from Grade 4 to age 15 years (the oldest age for which mean arterial pressure was assessed thus far), these associations were not robust to the inclusion of covariates and the modeling of second-order stability processes.