The structure of D 1.36ReO 3 has been determined by a room temperature powder neutron diffraction study. The unit cell is body centered cubic (space group Im3) and contains eight formula weights ( a = 7.497 ± 0.001Å). A least squares method based on peak intensities was used to refine the structure. The rhenium atoms lie on the special perovskite sites and are surrounded by distorted octahedra of oxygen atoms which are displaced towards the vacant perovskite A sites. The deuterium atoms are statistically distributed over 72 possible sites in the unit cell, as OD bonds.