Process for producing n-glycyltyrosine

Provided is a process for efficiently producing N-glycyltyrosine of high purity represented by the following formula: a salt thereof, or a solvate thereof, which comprises adding dropwise to an aqueous suspension of tyrosine or a salt thereof 2 equivalents or more of a haloacetyl halide and an aqueous solution of an inorganic base simultaneously in the presence or absence of an organic solvent, and subjecting the resulting N-haloacetyltyrosine to a reaction with an ammonium ion. Also provided are N-glycyl-L-tyrosine dihydrate having the crystal structures showing specific diffraction patterns in X-ray powder diffraction and processes for producing the same which are characterized by comprising crystallizing the dihydrate from an ethanol-water mixed solvent or water.