Tantalum exchanged tungstophosphoric acid (Ta(x)TPA) catalysts were prepared and studied for the synthesis of glycerol carbonate from glycerol and urea. These catalysts were characterized by FT-IR, X-ray diffraction, Laser Raman, pyridine adsorbed FT-IR and temperature programmed desorption of ammonia. The characterization results indicate that the Keggin ion structure of tungstophosphoric acid (TPA) is intact. The activity towards the synthesis of GC over the Ta(x)TPA catalysts depended on the number of Ta5+ ions exchanged in the secondary structure of heteropoly tungstate. Presence of Ta in TPA leads to the generation of Lewis acidic sites. Catalysts with partially exchanged Ta with the protons of TPA showed high activity due to the presence of both Bronsted and Lewis acidic sites. Different reaction parameters such as reaction temperature, glycerol to urea molar ratio and catalyst loading were studied and optimum conditions were established. These catalysts exhibited reusability. [GRAPHICS] .