Carboxylated styrene-butadiene rubber (XSBR) is selectively hydrogenated by diimide reduction technique in latex stage using hydrazine hydrate, hydrogen peroxide and Cu+2 as catalyst. The products are characterised by IR and NMR spectroscopy. Dynamic Mechanical Properties and Transmission Electron Micrographs of the hydrogenated products confirm the existence of ionic aggregates involving carboxyl (-COOH) groups of the substrate and externally added Cu+2 ions. Longer reaction time and higher amount of catalyst are required for hydrogenation of XSBR compared to that of SBR. An increase in the amount of carboxyl group decreases the extent of reaction.