To provide a method for producing, in high yield, 3,6-bis substituted amino-2,5-pyrazinecarbonitriles stably on a commercial scale.

This method produces 3,6-bis substituted amino-2,5- pyrazinecarbonitriles, expressed by formula I (R is a 1-16C alkyl or benzyl which may have a substituent), by reacting 3,6diamino-2,5-pyrazinecarbonitrile with an alkylation agent in the presence of a base, comprising a step of uniformly dissolving 3,6-diamino-2,5-pyrazinecarbonitrile in an organic solvent and another step of adding the alkylation agent and base to the uniform solution of 3,6-diamino-2,5-pyrazinecarbonitrile.