N-chloroacetylglutamine is produced by reacting chloroacetyl chloride with an alkaline aqueous solution of glutamine the presence of a water-immiscible organic solvent, separating an aqueous layer by liquid-liquid separation, and crystallizing N-chloroacetyl-glutamine from the aqueous layer under acidic conditions. N-Chloroacetyl-glutamine useful as an intermediate for producing glycyl-L-glutamine which has higher stability than L-glutamine and is used as a component of an infusion solution can be obtained with high efficiency at low cost.
