Dielectric, hysteresis, and scanning electron microscope studies on L-tyrosine doped triglycine sulfate (TyTGS) are reported. Increase in the relative permittivity compared to triglycine sulfate is observed on the doped crystal. Low frequency dielectric relaxation process is found to be modified in TyTGS crystals. No significant change in the spontaneous polarization compared to pure triglycine sulfate is observed. Increase in the coercive field in TyTGS compared to pure triglycine sulfate suggests that the dopant hinders the domain wall motion. Lens shaped domains, typical of triglycine sulfate are also observed on TyTGS crystal. (C) 2002 Elsevier Science Ltd. All rights reserved.