A model for the crystalline structure of Ba2YCu0.25W0.75O6 solid solution is given. The model proposed a perovskite ordered structure, with a cubic unit cell made from eight perovskite-like units and having a symmetry described by the space group Fm3m. The crystalline structure was refined by the Rietveld technique, giving RF=0.048 for 82 reflections. The solid solution was characterized by the following parameters: Z=4, Mr=613.2, a=8.43630(8) Å, V=600.42(1) Å3, Dx=6.78 g cm−3, μ=209.04 mm−1, and F(000)=1047. The model assumed that copper and tungsten atoms, which were ordered with Y atoms, had the same local environment. Therefore, it was only a first approximation to the crystalline structure.