Epoxidized natural rubber (ENR) is fairly stable in its latex state. Only a small amount of the epoxide groups were converted to diols when the latex was boiled under mildly acidic or alkaline pH. Although the small amount of diols could not be determined accurately by H-1 nuclear magnetic resonance (n.m.r.), their presence could be demonstrated by the degradation reaction using lead tetraacetate. The formation of -OH and carbonyl groups after the degradation could be clearly seen in the infra-red spectra. Higher level of diols could be introduced by reacting ENR-50 dissolved in toluene with a mixture containing water and acetic acid in tetrahydrofuran at 60 degrees C. The amount of conversion of epoxide to diol increases with reaction time, and up to 23 mol% of diol in the rubber chain can be achieved after 24 h of reaction. The extent of conversion can be determined from the H-1 n.m.r. spectra of the samples. The ENR containing diols in the main chain could serve as a good intermediate for further chemical modifications. For example, cleavage of the diol groups with specific reagents could offer a convenient route to the production of liquid ENR.