In this work, the nanosized magnetic Fe 3 O 4@ SiO 2@ TiO 2 photocatalyst was prepared by sol-gel methods. First the nuclei of magnetite nanoparticles were prepared by co-precipitation of iron (II&III) salts solutions. Secondly, the magnetite nanoparticles were dispersed in ethanol using sonication, and solutions of both ammonia and tetraethoxysilane were added to the suspension under intense stirring, since it was suggested that the introduction of an intermediate passive SiO 2 layer between the Fe 3 O 4 and TiO 2 phases inhibits the direct electrical contact and hence prevents the photodissolution of the magnetite phase and deterioration of the surface photocatalytic properties. Finally, solution of tetrabutoxytitanium was added dropwise to the mixture of Fe 3 O 4@ SiO 2 nanoparticles under sonication & intense stirring. The resulting particles were separated using a magnet, washed and dried to constant weight, the yield was 70%. The photocatalytic activity of Fe 3 O 4@ SiO 2@ TiO 2 nanoparticles was investigated by photodegradation of methyl orange in aqueous solution under UV light irradiation. The photodegradation dynamics revealed that even though the oxidation rate decreases over time, about 90% of methyl orange is oxidized during the first 35 min.