The magnetic and transport properties of La2/3−xNdxCa1/3MnO3(x=0–0.67) are studied. Two magnetic transitions occur in compounds with compositionx=0.1–0.4, leading to a low moment state at high temperature and a high moment state at low temperature. A metal–insulator transition was observed forx≤0.4 between the two magnetic transitions. An electronic and magnetic phase diagram is depicted on a temperature–tolerance factor plane. The interesting feature of this diagram is the appearance of a new metamagnetic phase. Present investigation suggests that the tolerance factor is not the only parameter determining the lattice effects. ©1996 American Institute of Physics.