Boehmite nanoparticles were covalently functionalized by 3-(trimethoxysilyl)-propylamine to support H5[PMo10V2O40] and H5[PW10V2O40] Keggin type heteropolyacids. After characterizing these catalysts by FT-IR, PXRD, TG/DTA, CHN, ICP, and TEM techniques, they were applied to the epoxidation of cis-cyclooctene. The progress of the reactions was investigated by gas-liquid chromatography and the catalytic procedures were optimized for the parameters involved, such as the solvent and oxidant. The results showed that 20 mg of supported H5[PMo10V2O40] catalyst in 2 ml C2H4Cl2 with 0.5 mmol cyclooctene and 1 mmol tert-butyl hydroperoxide at reflux temperature gave 98% yield over 60 minutes. Recycling experiments revealed that these nanocatalysts could be repeatedly applied up to four times for a nearly complete epoxidation of cis-cyclooctene. The optimized experimental conditions were also used successfully for the epoxidation of some other alkenes such as cyclohexene, styrene and α-methyl styrene.