Genistein, the principal soy isoflavone, is a molecule of great interest as an innovative chemotherapeutic agent or as a lead-compound in anticancer drug design. To enhance intrinsic activity of genistein and to explore its pharmacophoric potential, its glycosidic derivatives were synthesized. On the basis of structural features and calculated lipophilicity coefficient (ClogP) the derivatives were classified as hydrophilic (i.e. those containing free sugar moiety) or lipophilic (i.e. those with alkylated or acylated sugar hydroxyls). The in vitro cytostatic and cytotoxic studies showed hydrophilic glycosides to be practically inactive against human cancer cell lines when compared to the free aglycone. On the contrary, lipophilic glycosides were significantly more active than the parent isoflavone although the correlation between ClogP and the activity was not clear. On the basis of GI50 and LC50 values two of the most active glycosides were found to be several times more potent in their cytostatic and cytotoxic effect than genistein. Additionally all lipophilic glycosides were revealed to exhibit different mode of action in comparison to genistein. It may suggest that these compounds do not undergo rapid biodegradation, either in culture media or inside cells, and exert their biological effects primarily as intact molecules.