Spherical mesoporous SiO2 and SiO2-TiO2 particles were synthesized by sol-gel method using W/O emulsion under microwave irradiation. In SiO2 system, W/O emulsion was prepared by mixing partially hydrolyzed Si(OC2H5)(4) aqueous solution including C(18)TAC as template with n-hexane solution including polyglycerol polyricinalate as emulsifier. In SiO2-TiO2 system, Ti(OC2H5)(4) capped by acetylacetone was added to the aqueous phase. In both cases, spherical products were synthesized by heating of W/O emulsion for 30 min under microwave irradiation. The specific surface area and pore size of spherical products were 800 m(2)/g and 1.6 nm, respectively, which indicates that the spherical products are mesoporous. These results suggest that sol-gel reaction in water phase proceeds rapidly because microwave quickly and selectively heats up the aqueous solution.