Phosphorus is an expensive ingredient in pigs diets, despite this it is often given to pigs in excess and therefore is not digested and then spread in fields as manure. The objective of this study was to determine the effect of changes in dietary true digestible calcium (Ca) to true digestible phosphorus (P) ratio on growth performance, efficiency of P utilization and manure P excretion. The first experiment involved a small group of pigs put on one of two diets, each was based on corn and soybean meal and two levels of Ca and P with the lower nutritional diet having 25.5% corn starch. There was also a digestible marker in each diet. Pigs who were on the low nutrient diet had reduced ADG, and had a decreased feed conversion ratio. The second experiment involved six diets, which were all corn and soybean meal based but each with a different ratio of Ca and P. Some results from the second experiment were that changes in the Ca and P ratio had no effect on the average daily feed intake. Changes did have an effect on ADG and feed conversion ratio with positive responses in diets 2-4 which had ratios of 0.74-0.81:1 (Ca:P). It was concluded that changes in dietary Ca to P ratio have significant effects on growth performance. Dietary true digestible Ca to true digestible P ratio of 0.90:1 to 1.10:1 equivalent to total Ca to total P ratio of 0.70:100 to 1.20:1:00 may be optimal for feeding grower pigs.