The relative reactivity of bromination of regioisomers of cresol by N-bromopthalimide in aqueous medium has been studied at various temperatures. The reactions has been found to be of second order. The specific reaction rates for the bromination of ortho, meta and para cresol has been found to be 175 M^-1S^-1, 7398 M^-1S^-1 and 410 M^-1S^-1 respectively. The energy of activation (Ea), frequency factor (A) and entropy of activation (Ds^#) has been evaluated. Due to rapidity of reactions in aqueous medium, a special technique is necessary. Rotating platinum electrode is used to measure rapid kinetics. kinetic and thermodynamic data has been used to determine the relative reactivity of the isomers.