New lead-free (Bi1-x-yNdxNa1-y)(0.5)BayTiO3 ceramics were prepared by a conventional ceramic technique and their dielectric and piezoelectric properties were studied. X-ray diffraction studies reveal that Nd3+ and Ba2+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a new solid solution with a pure perovskite structure, and a morphotropic phase boundary (MPB) of rhombohedral and tetragonal phases is formed at 0.04 < y < 0.10. The partial substitutions of Nd3+ and Ba2+ decrease effectively the coercive field E-c and increase significantly the remanent polarization P-r. Because of lower E-c, larger P-r and the formation of the MPB, the piezoelectric properties of the ceramics are significantly enhanced at x/y = 0.02/0.06: d(33) = 150 pC/N and k(p) = 30.5%. The ceramics exhibit relaxor characteristic, which is probably resulted from the cation disordering in the 12-fold coordination sites. The depolarization temperature T-d shows a strong compositional dependence and reaches a minimum value at the MPB. The temperature dependences of the ferroelectric and dielectric properties suggest that the ceramics may contain both the polar and non-polar regions near the depolarization temperature T-d, which cause the polarization hysteresis loop become deformed near/above T-d. (C) 2009 Elsevier B.V. All rights reserved.