In the present study, ENRs with different mole% of epoxide groups are used as compatibilizers in a range of 2.5–15 phr for virgin NR/silica compounds. The effects of ENR contents and mole% of epoxide are investigated. The epoxide groups are supposed to interact with the silanol groups of the silica and so to improve silica–rubber compatibilization, while the unmodified parts of the ENR structure is compatible with the NR matrix.