Polystyrene-supported benzyltributylammonium borohydrides were prepared and the reducing properties of the reagents were studied in the reduction of aldehydes, ketones, esters and imines. The reagent exhibited chemoselectivity towards reduction of aldehydes in presence of ketones. The reducing efficiency of the reagent was optimized by investigating the effect of macromolecular characteristics of the polymer support like nature and extent of crosslinking, presence of spacer groups etc. on the reduction of 4-nitrobenzaldehyde to 4-nitrobenzyl alcohol. The progress of the reaction was monitored spectrophotometrically at λmax 252 nm. The effect of the reaction conditions like temp, solvent used and the concentration of the polymeric reducing agent were also analyzed. The reducing agent derived from 2 % butanediol dimethacrylate crosslinked polystyrene resin with a PEG (600) chain spacer between the polymer backbone and the borohydride moiety, was found to be the optimum reagent. DCM and THF were found to be ideal solvents for reduction and maximum rate was found at 55°C in THF. The substrates were reduced at faster rates by the polymer bound borohydride reagents in presence of acid catalysts.