Abstract: New tetrazole-containing derivatives of 2,4-diamino-1,3,5-triazine were synthesized. The cytotoxic activity of the obtained compounds against Huh-7 and HeLa tumor cell lines was studied by the MTT test. The most significant antitumor activity was shown by 1,3,5-triazines containing a 5-phenyltetrazol-2-ylacetohydrazide fragment. The resulting compounds showed practically no cytotoxic effect on non-tumor cells of the human embryonic kidney line HEK293.