Altogether, a growing amount of clinical and experimental data suggests that lipids may be important in the development and progression of chronic renal injury. Abundant clinical data have demonstrated that hyperlipidemia is associated with diabetes, decreased renal function, and the nephrotic syndrome. Although clinical correlations between plasma lipid levels and renal dysfunction do not prove a cause-and-effect relationship, potentially injurious lipid abnormalities are invariably present in those patients most likely to progress to end-stage renal disease. In several animal models, pharmacologic treatment of lipid abnormalities has been shown to ameliorate renal disease. Moreover, experimental data suggest that lipid-induced alterations in a number of immune and nonimmune mechanisms could explain the association between lipids and renal injury. A better understanding of these alterations and mechanisms may ultimately lead to more effective treatment of patients with chronic progressive renal disease.