A number of ordered perovskite‐type compounds A2BB′O6, in which B and B′ are, respectively, a 3dtransition metal cation and a diamagnetic cation, undergo antiferromagnetic transitions. The latter have been interpreted in terms of antiferromagnetic ordering of the second kind arising from appreciable superexchange interactions over quite long distances involving two anions and one diamagnetic cation. A neutron diffraction study has been made of polycrystalline samples of two such compounds, Ba2CoWO6and Ba2NiWO6. The crystal structures are cubic, and there is a slight displacement of the oxygen ions from the ideal perovskite positions towards the more highly charged W ions of about 0.1 Å. At 4.2°K the magnetic unit cell edge is double that of the crystallographic cell in both compounds and the observed magnetic peaks are consistent with ordering of the second kind. The spin direction in Ba2NiWO6is perpendicular to the [111] axis, but in Ba2CoWO6it appears to lie roughly 20° from the [111] axis.