The practical synthesis of pseudonucleosides incorporating thiourea derivative by coupling of monosaccharides (D-galactose, D-glucose and D-xylose) per-O-acetylated glycosyl isothiocyanates and different heterocyclic hydrazide derivatives is reported. The method involves the preparation of per-O-acetylated glycosyl isothiocyanates from per-O-acetylated sugars (two-step synthesis), which couple with heterocyclic hydrazides from amines to give thiourea-linked pseudonucleosides. All newly synthesized pseudonucleosides were assayed against human lung cancer-cell lines (PG) and human liver cancer-cell lines (BEL-7402) in vitro. The 2-(4-methoxybenzamide)-benzoimidazole-1-yl-acetyl pseudonucleosides showed moderate inhibition against these two cancer-cell lines with EC(50) from 22.8 to 76.4 microM and from 54.9 to 82.4 microM, respectively. And the other compounds did not demonstrate any significant cytotoxicity even at concentrations up to 200muM.