A series of 6,7-disubstituted-3-{2-[4-(substituted)piperazin-1-yl]-2-oxoethyl}quinazoline- 2,4(1H,3H)-dione derivatives (7-34) were synthesized and their structures were elucidated on the basis of analytical and spectral (UV, IR, 1H-NMR, 13C-NMR and MS) data. These synthesized compounds were evaluated for their in vitro cytotoxicities against a panel of three human cancer cell lines. According to the cytotoxicity screening results, 3-{2-[4-(4-chlorobenzyl)piperazin-1-yl]-2-oxoethyl} quinazoline-2,4(1H,3H)-dione (7) presented the highest activity against HUH-7, MCF-7 and HCT-116 cell line with the IC50 values of 2.5, 6.8 and 4.9 µM, respectively.