Availability of crystalline amino acids has allowed reduction in the crude protein (CP) content of swine diets. Low CP diets supplemented with essential amino acids can decrease nitrogen excretion in the manure and is often more cost effective than using an additional amount of the particular protein source. Two experiments were conducted to study the performance of growing and finishing pigs fed high and low CP (4% lower) diets supplemented with crystalline amino acids. These experiment confirmed that performance could be maintained when either high or low crude protein diets are fed if amino acids are balanced and the diets are formulated to be similar in net energy.