Because of the ''graying'' of the population there is increasing interest in age-related changes in organ physiology. Impairment of lipid absorption, if present, could lead to malnutrition in the elderly while increased uptake of cholesterol could contribute to the rise in serum cholesterol levels seen in older individuals. This review critically analyzes the available information on age-related changes in digestive and absorptive physiology of lipids. Overall, the data suggest that lipid digestion and absorption are, in general, well-preserved in aging. However, intercurrent illness or experimental stress may produce impairment in aging animals and humans that are not seen in younger controls. Areas deserving more detailed study are identified in this review and include intestinal motility, adaptation to stress, and assembly and transport of lipoproteins from enterocytes to lymph.