The heterogeneous catalytic transfer hydrogenation of styrene-butadiene rubber (SBR) by the use of limonene as hydrogen source and as solvent in the presence of Pd/C as catalyst has been studied. The influence of the heating time on the reduction and on the structure of the donor was studied. Partial hydrogenations of the olefinic bonds of SBR are obtained when a mixture of limonene, SBR and 10% Pd/C is refluxed with vigorous stirring for 50-200 minutes.