The experiment was conducted to determine calcium and phosphorus requirements for White Leghorn starting chicks. Six experimental diets of various amounts of calcium(0.6, 0.68, 0.83, 0.85, 0.75 and 1.0%) and phosphorus (0.6, 0.68 and 0.75%) were fed the female chicks of 0-4 weeks of age. All experimental diets were primarily composed of corn and soybean meal with 5% fish meal, and graded levels of calcium and phosphorus were furnished by calcium carbonate, dicalcium phosphate and tricalcium phosphate. Calcium and phosphorus requirements were determined by measuring weight gain, feed efficiency and percent tibia ash. 1) It was indicated that calcium requirement for normal growth and normal bone development of 0-4 weeks of age was 0.85% in diet, which was a little lower than what was recommended by National Research Council. 2) Total phosphorus required for normal growth and percent bone ash was 0.6% in diets. 3) Optimum calcium: phosphorus ratio in diets was indicated to be 1.42:1. 4) It was suggested that about 0.2% inorganic phosphorus was required for normal growth and bone development, and the availability of organic phosphorus appeared to be much higher than what had been thought.