Self-evaluations of general health are among the most widely-used measures of health status in research on the need for and outcomes of medical care. Yet, researchers know little about the psychological processes behind them. This study looks at whether such evaluations, often referred to as self-rated health, shift in what they measure as individuals age. Although several perspectives point to age-related shifts, few researchers have explicitly tested these perspectives against each other. The study tests several competing hypotheses using a large, nationally representative, and longitudinal data set. The results suggest two countervailing trends. First, the correspondence between functional limitations and self-rated health declines, especially after the age of 50. Similarly, the correspondence between a variety of chronic conditions and self-rated health, while strong, declines precipitously. Both of these findings are consistent with the idea that individuals evaluate their health through a process of social comparison and, in so doing, are able to maintain an elevated sense of general health even as they age. Yet, the results also suggest that the correspondence between depressive symptoms and self-rated health increases steadily throughout the life course. Indeed, after the age of 74, the correspondence between self-rated health and some common symptoms of depression becomes stronger than the correspondence between self-rated health and several chronic, and often fatal, somatic conditions. The implications of this crossover for both theory and policy are discussed. Among other things, the crossover has important implications for the detection and treatment of depressive symptoms in later life.