The present invention is directed to a process for synthesizing an epoxidized polymer that includes the steps of: (1) preparing a cationically stabilized polymer latex containing at least one conjugated diolefin monomer in a first stage, (2) treating the polymer latex from step (1) with formic or acetic acid and hydrogen peroxide, and (3) allowing the mixture to react for a predetermined time and predetermined temperature to attain the desired level of epoxidation.