Weanling rats were fed a casein-based diet containing either 150 ppm cadmium, 500 ppm nickel, or the combination of these metals for 16 wk. Blood pressure of rats fed the diet with cadmium decreased after 8 wk, but this effect was counteracted by dietary nickel. Cadmium caused a depletion of iron and resulted in an accumulation of zinc in liver and kidney of rats. Nickel partially counteracted the iron loss due to cadmium. In a second experiment, the inclusion of 10 or 20 ppm cadmium in drinking water for 24 mo did not result in elevated blood pressure in normal or genetically hypertensive rats. Cadmium had no effect on the plasma renin levels in either experiment. Low intake of cadmium (10 or 20 ppm) in drinking water resulted in elevated cadmium content in hair. Thus, our data do not indicate that high levels of cadmium contribute to hypertension.