A new series of 2-amino-6-(2-alkyl or arylidenehydrazinyl)-4-(dialkylamino)pyrimidine-5-carbonitriles, 5-24, were synthesized in satisfactory overall yield, using 2-amino-4-(dialkylamino)-6-hydrazino-5-pyrimidinecarbonitriles 3, 4, as key intermediates, by applying classical synthetic methods to construct the hydrazone moiety at C-6 of the pyrimidine ring. Hydrazinopyrimidine derivatives 5-24 were evaluated for their in vitro anticancer activity toward cell lines of nine different types of human cancers. Some of the newly prepared compounds demonstrated inhibitory effects on the growth of a wide range of cancer cell lines generally at 10(-5)M level and in some cases at 10(-7)M concentrations.