Abstract: The kinetics of the oxidation of the mandelic by N-bromoanisamide has been studied in 40% acetic acid medium in the presence HC1O4 and of [Hg(OAc)2]. The reactions exhibit a first order rate dependence with respect to oxidant and fractional order with respect to substrate. The reaction rate decreases slightly with increasing the concentration of [H+] and retarded by the addition of anisamide, (as one of the oxidation product of oxidant). The decrease in dielectric constant of the medium decreases rate of the reaction. Increase in ionic strength, by the addition of sodium perchlorate has no effect on the rate constant.The effect of temperature on the reaction has been investigated in the temperature range 308-323 K.The activation parameters were calculated and a possible operative mechanism was proposed.