The present invention provides a method for producing a high purity N.sup.4-acylcytidine derivative. More specially, the invention provides a compound represented by the formula (1): 1 wherein R1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, a perfluoroalkyl group having 1 to 4 carbon atoms, or a halogen atom; R2 is a hydrogen atom, an alkoxyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms with a substituent, or a halogen atom; R3 represents a methyl group or a phenyl group; and M represents a positive ion of an alkali metal or an alkaline earth metal, and a compound represented by the formula (2): 2 wherein R1, R2, and R3 are as defined above, produced by using the compound represented by the formula (1).