Cr doping inPr0.5Ca0.5MnO3is known to destroy the low-temperature antiferromagnetic charge-ordered state and to induce a ferromagnetic component as well as colossal magnetoresistance properties. Effects of Cr doping on the magnetic and nuclear structures are studied here by neutron diffraction forPr0.5Ca0.5Mn0.95Cr0.05O3.It is shown that, at low temperature, the strongly distorted charge ordered structure usually observed inPr0.5Ca0.5MnO3is replaced by a ferromagnetic phase in which the basal-plane distortion of theMnO6octahedra has disappeared, in agreement with the restoration of the double–exchange interactions. ©1998 American Institute of Physics.