The synthesis of the 3′-fluoro-derivatives of 5-amino-1-(β-D-ribofuranosyl)imidazole-4- carboxamide (AICA-riboside) and the isomeric 4-amino-1(β-D-ribofuranosyl)imidazole-5- carboxamide (iso-AICA-riboside) are described. Structures were confirmed by elemental analysis, UV and 1H NMR spectroscopy. The anti-viral and anti-cancer activities of these imidazole nucleosides were tested.