NuPro®, a yeast-derived protein source, is an alternative to spray-dried plasma in diets for newly weaned pigs. There is no information about the amino acid digestibility in NuPro® during the immediate post-weaning period. The objective of this experiment was to determine the ileal digestibility of amino acids in a yeast-derived protein (NuPro®, Alltech Inc.) in 4-wk old piglets. It was found that NuPro® is a source of highly digestible amino acids for newly weaned pigs. The data obtained in this experiment on standardized and apparent ileal digestibility values for NuPro® may be used in diet formulation for pigs between 20 and 30 d of age.