Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets for pigs. Different technologies are used to develop high protein corn co-products, but in addition to providing amino acids to the diets, high protein corn co-products also provide energy to the diets. The energy concentrations in corn protein may depend on the concentrations of fat, carbohydrates, and protein in sources of corn protein. Newly developed corn proteins contain 40 to 50% crude protein. There are, however, limited data on how differences in the chemical composition of different sources of corn protein influence the concentrations of digestible energy (DE) and metabolizable energy (ME) when fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the apparent total tract digestibility (ATTD) of gross energy (GE) and concentrations of DE and ME among 3 sources of corn protein when fed to weanling pigs.