Abstract: A series of 4(3H)-quinazolinone derivatives bearing dithiocarbamate side chains have been synthesized through the reaction of 6-bromomethyl-2-methyl-4(3H)-quinazolinone with CS₂ and various amines in the presence of anhydrous K₃PO₄, and their structures were confirmed with ESI-MS, ¹H NMR, elemental analysis or HRMS. The target compounds 8a-8q were tested for their in vitro antitumor activity against human myelogenous leukaemia K562 and human Hela cell lines by means of colorimetric MTT assay. Among the tested compounds, 8q exhibited in vitro inhibitory activity against K562 and Hela cells with IC₅₀ values of 0.5 and 12.0 μmol·L^-1, respectively. Therefore, compound 8q is worthy to be a lead compound for the design and synthesis of new antitumor agents.