Single crystals of triglycine sulphate (TGS) doped with L-alanine and L-valine were grown in aqueous solutions by a slow cooling method. The changes in solubility and metastable zone width due to the doping have been studied. The pyroelectric and dielectric measurements made on these samples reveal that the doping of amino acids enhanced the ferroelectric transition temperature (T-c) and pyroelectric figure of merit. The microhardness of doped TGS crystals was found to be lower than that of pure crystals. FTIR spectra of the doped crystals show broadening of peaks, compared to those of pure crystals.