Abstract: This paper reports the synthesis and the antimalarial and anticancer activities of some derivatives of 2,4-diamino-5-methyl-6-substituted benzylaminoquinazolines. These compounds were synthesized by condensation of 5-methyl-2,4,6-triaminoquinazoline with substituted benzyaldehyde to produce Schiff base, followed byr eduction, formylation or nitrosation. The suppressive therapeutic effects against Plasmodium berghei in mice showed that the suppressive rate of three compounds (Ⅳ_2,5,6)was 100 per cent at the dosage 5 mg/kg. The anticancer activity in vitro showed that Ⅱ₇, and Ⅲ₈ had the strongest inhibition and their IC₅₀ against L1210 Leukemia cell were 3.910×10^-3 μg/ml and 6.172×10^-3 μg/ml.