||Lead (Pb) (200 ppm) was administered via drinking water to rats for nine weeks. In addition, the rats were grouped so that they received 75, 100, 150 and 250% of the minimum daily requirements (MDR) of calcium (Ca), iron (Fe), and magnesium (Mg) as required for normal growth. The exposures were arranged so that no more than one element was varied within the same animal groups, while maintaining 100% of the MDR of all other elements and nutrients. Blood lead analysis were performed at 0, 1, 2, 3, 7, 8, 9 weeks after exposure. Food and water consumptions and body weights were measured each week (0-9). Some gross differences were seen both within and among the groups with respect to milliliters water consumed vs. body weight and grams of food consumed vs. body weight. During the first few weeks of exposure, the mean blood lead in animals fed 75% MDR of Ca, Fe, and Mg at appeared less than those receiving 100% MDR of the corresponding elements. There was a decrease in mean blood lead concentration in animals receiving 150 and 250% of the MDR of Fe at the 7-9 week time period, however, this was probably due to a slight decrease in water consumption during the time period.