1. Endothelin has significant effects on renovascular, glomerular and tubular function. 2. Endothelin causes severe renal vasoconstriction, resulting in a decrease in renal blood flow and glomerular filtration rate. 3. Endothelin can inhibit sodium reabsorption and, in the rat, vasopressin-induced water transport. 4. The endothelin receptor subtypes mediating renovascular and tubular effects of endothelin may differ between species. 5. Renal endothelin production, metabolism and receptor binding is altered in a number of renal diseases, including acute and chronic renal failure and cyclosporine and radiocontrast nephrotoxicity. 6. Endothelin receptor antagonists or antibodies can attenuate the severity or progression of a number of renal diseases.