The kinetics epoxidation of rubber seed oil (RSO) by peroxyacetic acid generated in situ were studied at various temperatures. It was foound that epoxidation with almost complete conversion of unsaturated carbon and negligible oxirane cleavage can be attained by the in situ technique. The rate constant for epoxidation of RSO was found to be of the order ot 10-6 1 mol-1 s-1 and activation energy of epoxidation of 15.7 kcal mol-1 was determined. Some thermodynamic parameters: enthalpy, entropy and free energy activation of 15.2,-31.94 and25.44 kcal mol-1 repectively were obtained for the epoxidation of RSO. The kinetic and thermodynamic parameters of epoxidation obtained from this study indicate that an increase in the process temperature would increase the rate of epoxide formation.