Keto C-glycoside-fatty acid conjugates were synthesized from 6-hydroxy 2- and 4-keto unsaturated D-C-glycosides. These compounds were tested for cytotoxic activity against LFC12A cells (Rat hepatocarcinoma cells). The introduction of a liptd chain to 2-keto C-glycosides induced a drop in the cyctotoxic activity of these compounds. On the other hand 4-keto unsaturated C-glycoside-fatty acid conjugates possessed ICs values of 0.7-0.001 PM with 21 being the most potent.