After the administration of equal doses of sodium dichromate, chromium concentrations in the kidney were lower in young than in adult rats. To test the age-dependent sensitivity to the nephrotoxicity of dichromate, young and adult rats were given doses to achieve identical chromium concentrations in the kidney. At equal renal concentrations, young rats had less functional and morphological damage than adult rats. As phenobarbital treatment in young rats enhanced the symptoms of nephrotoxicity and metyrapone treatment in adult rats decreased the symptoms of nephrotoxicity, age-dependent differences in chromate nephrotoxicity may be linked to an increase in the enzymatic reduction of Cr(VI) with age.