Selective limonene epoxidation was carried out over a heteropolyacid anchored on Amberlite IRA-900, using hydrogen peroxide as the oxidant. The effects of various parameters such as the concentration of catalyst, H2O2, limonene, and water on the rate of reaction have been studied. A mechanism similar to that proposed under the so-called Ishii-Venturello chemistry was used to develop a kinetic model based on the Langmuir-Hinshelwood formalism. This includes the adsorption of reactants and solvent on the catalyst. Although the kinetic model showed to be in agreement with the experimental results, water did not appear to adsorb on the catalytic sites. Furthermore, the influence of epoxide addition to the reaction mixture was examined. Epoxide deactivates the catalyst and the reaction practically stops when the amount of epoxide added is equivalent to about 160 turnovers. Notwithstanding, the catalyst is reactivated after being washed with acetone. (C) 2002 Elsevier Science B.V All rights reserved.