Imports of milk protein concentrates (MPCs) are increasingly entering the United States with minimal trade restrictions. MPC is a general reference to a dried protein product derived from milk using a technology known as "ultra filtration." Two questions are addressed in this article. First, did the combination of relaxed import restrictions, low world prices for protein, and relatively high domestic support levels for nonfat dry milk encourage imports of MPCs? Second, did increased imports of MPC displace domestic use of nonfat dry milk and thereby increase government purchases under the dairy price support program? This study has implications for U.S. trade policy.