The kinetics of uncatalysed and catalysed oxidation of D-ribose by Cerium(IV) has been studied in acidic medium in the temperature range 303-338 K. The reaction has been found to be first order with respect to [D-ribose] in both uncatalysed and catalysed reactions. The rates follow first order kinetics in [Ir(III)] catalysed oxidation reaction. The effect of [HSO4- ] has also been observed. The increase in ionic strength of the medium decreases the rate of uncatalysed reaction while increases catalysed reaction. A 1:2 stoichiometry is observed in the oxidation. From the effect of temperature on the reaction rate, the Arrhenius and activation parameters have been calculated. A suitable mechanism has been proposed and a rate law explaining the experimental results is derived.