The oxidation of a number of linear, branched, and cyclic olefins catalyzed by the large-pore Ti-Beta catalyst in the presence of H2O2 and TBHP as oxidants has been carried out under mild conditions. The influence of the olefin structure on its reactivity towards oxidation has been studied. Depending on the particular olefin structure, the reaction rate was seen to be mostly influenced by the intrinsic reactivity of the double bond, diffusional limitations, or steric factors. The latter were seen to be more pronounced in the oxidations with TBHP, owing to the bulkier Ti-OO-C(CH3)(3) species which would be formed inside the zeolite pores. Oxidations with TBHP also proceeded at a lower rate than with H2O2. Close to 100% selectivities to epoxides were found when TBHP was used as oxygen donor. In the case of H2O2 solvolysis of the oxirane ring in methanol solutions was the major secondary reaction observed. The rate of this reaction was seen to depend on the structure of the epoxide formed in the first step. In both cases, very little peroxide decomposition was observed under the reaction conditions used.