Titanium containing catalysts were synthesized using hydrophobic silicas as support; they were tested for the epoxidation of cyclohexene with aqueous H2O2. It is shown that, despite the low number of surface silanols and the presence of surface hydrophobic methyl-silane entities, tetraneopentyltitanium TiNp4 reacts with the surface silanols, with formation of the complex =SiOTiNp3, 1, chemically bonded to the surface. Hydrolysis of this surface complex 1 leads to the formation of =SiOTi(OH)(3); contrary to what was observed with hydrophilic silica supports, the anchoring bond =SiO-Ti is maintained. Calcination of 1 decomposes the silica surface modifying methyl groups, SiMe3 to Si(OH)(3); the chemical environment of Ti is then no longer hydrophobic in character; titanium remains very well dispersed. The two types of solids catalyze the epoxidation of cyclohexene with aqueous H2O2, with an epoxidation yield and selectivity significantly higher than those obtained with the analogs supported on hydrophilic silicas. A zirconium containing catalyst synthesized in a similar manner from ZrNp4 and a hydrophobic silica shows also enhanced selectivity or epoxide formation; interestingly; the rate of the successive decomposition of the epoxide is lowered. These properties are explained by the achievement of a better isolation of the Ti and Zr active sites on the hydrophobic silicas.