In this study, the inducible function of sodium nitroprusside (SNP, a nitric oxide donor) was evaluated based on the changes in some biochemical characteristics of mungbean (Vigna radiata (L.) Wilczek cv. DX208) involving resistance to cowpea aphid (Aphis craccivora Koch). SNP treatment was sufficient to increase content of chlorophylls, reduced aphid-infested damage, accumulated biosynthesis of antioxidants such as phenolic compounds and flavonoids in mungbean plants attacked by A. craccivora. Furthermore, SNP was also capable of either negatively altering the lifetime or diminishing fecundity of cowpea aphid. Those results demonstrated that SNP application improved the biochemical resistance of V. radiata cv. DX208 against its pest, A. craccivora.