Crystals of NiUS3 were obtained from the reaction of the elements Ni, U, S, and of GeI2 in a CsCl flux at 1173 K. Nickel(II) uranium(IV) tris-ulfide, NiUS3, has ortho-rhom-bic (Pnma) symmetry and crystallizes in the GdFeO3 structure type. The compound has a perovskite ABQ 3-like structure, with U occupying the inter-stitial sites of a NiS6 framework. The U atoms are coordinated by eight S atoms in a distorted bicapped trigonal-prismatic arrangement. The Ni atoms are coordinated by six S atoms in a slightly distorted octa-hedral arrangement. The asymmetric unit comprises one U site (site symmetry .m.), one Ni site (-1), and two S sites (1 and .m.).