The paper presents a simple synthesis of a series of new quinazolinone derivatives 13a-i. First, the reaction of 5-hydroxyanthranilic acid (11) with acetic anhydride at 160–180oC for 2 h gave the intermediate 12 in high yield. This intermediate was then reacted with amines in acetic acid at 180 oC for 14 h to afford new quinazolinone derivatives 13a-i in 69–92%. Synthesized compounds were structurally confirmed using spectroscopic methods: 1H, 13CNMR and MS spectra. The bioassay result using three cancer cell lines including SKLU-1 (lung cancer), MCF-7 (breast cancer) and HepG-2 (liver cancer) showed that only compound 13e exhibited significant cytotoxic effect against cancer cell lines tested with IC50 values of , and µg/ mL, respectively. | New quinazolinone derivatives: Synthesis and in vitro cytotoxic activity