Single crystals of L-tryptophan-doped triglycine sulphate (LTTGS) were grown by the low-temperature solution method. The effects of dopant on morphological changes were observed on the grown crystals. The grown crystals were characterized using powder X-ray diffraction (XRD), which shows that the LTTGS crystals are of monoclinic system. The presence Of L-tryptophan in TGS was estimated qualitatively by Fourier transform infrared (FTIR) analysis. Microhardness studies carried out using Leitz Weitzler hardness tester at room temperature. The hysteresis studies were also carried out to understand the ferroelectric properties. (C) 2007 Elsevier B.V. All rights reserved.