Epoxidized natural rubber (ENR) based nanocomposites were prepared by mixing ENR latex (epoxide content of 35 mole%) with silica nanoparticles (SiO2). SiO2 were previously treated with 3-aminopropyltriethoxysilane (APS) and 3-methacryloxypropyltrimethoxysilane (MPS). Morphological and mechanical properties of ENR/SiO2 composites were investigated. The dispersion of SiO2 in ENR matrix, which was characterized by SEM, indicated that the treated SiO2 exhibited better dispersion than that of the untreated SiO2. Moreover, it has been found that the modified SiO2 with either APS or MPS gave much significant reinforcing effect than the untreated one. However, the treatment of SiO2 nanoparticles with MPS resulted in better interfacial interaction when the APS treatment was compared.