PURPOSE: The hydrolyzate mixture of aminoacetonitrile is treated with a copper salt and the resultant copper glycine is allowed to react with an aldehyde to obtain the titled compound in the same high yield as in the reaction with an isolated pure glycine at low costs.

CONSTITUTION: An aqueous aminoacetonitrile resulting from reaction between formalin, hydrogen cyanide and ammonia is hydrolyzed in a basic condition to prepare an aqueous solution of alkali metal glycine salt. The solution is treated with a stoichiometric or excessive amount of an acid to obtain an aqueous solution containing free glycine or its acid adduct salt. A copper salt is added in portion to the aqueous solution under stirring at 40W70°C. The copper salt of glycine crystallizes out, but the copper salt of iminodiacetic acid, a by-product, remains in the solution. The separated copper glycine is allowed to react with an aldehyde is in another solvent or the unseparated copper glycine is allowed to react directly with an aldehyde to give the objective compound.