A series of conjugates of diterpenoid isosteviol (16-oxo--beyeran-19-oic acid) and -acetyl-D-glucosamine was synthesised and their cytotoxicity against several human cancer cell lines (M-Hela, MCF-7, Hep G2, Panc-1, PC-3), as well as normal human cell lines (WI-38, Chang liver) was assayed. Most of the conjugates were found to be cytotoxic against the mentioned cancer cell lines in the range of IC values 13-89 µM. Two lead compounds and showed selective cytotoxicity against M-Hela (IC 13 and 14 µM) that was two times as high as the cytotoxicity of the anti-cancer drug Tamoxifen in control (IC 28 µM). It was found that cytotoxic activity of the lead compounds against M-Hela cells is due to induction of apoptosis.