The methylation of dihydropyrimidinylidenecyanoacetic esters by various methylating reagents leads to better yields when anions of ylidene derivatives of pyrimidine are used. The structure of the products of N- and C-methylation formed and their ratio were established with the aid of the IR and UV spectra and by 1H and 13C NMR spectroscopy. The product of C-methylation contains a methyl group at the C(7) atom of the side chain, while the product of N-methylation contains a methyl group at the nitrogen atom of the pyrimidine ring. For 6-ylidene derivatives, N-methylation occurs at the heterocyclic atom distant from the tautomerizing chain. For 2-and 6-ylidene derivatives of pyrimidine, the ratio of the products of N- and C-methylation can be changed by varying the alkylating reagent.