Ytterbium(III) tetraaquatris(tetraoxorhenate(VII)), Yb(ReO4)3(H2O)4, was prepared by the reaction of Yb2O3 with concentrated HReO4 at room temperature. The colorless compound crystallizes in the monoclinic space group P21/n (No. 14) with four formula units per unit cell (a=730.5(1)pm, b=1484.1(5)pm, c=1311.7(2)pm, β=93.69(1)). The main feature of the crystal structure is the formation of chains ∞1[Yb(H2O)4(ReO4)2(ReO4)2/2] running along [100]. This arrangement shows distorted cubic antiprisms of [Yb(H2O)4(ReO4)2(ReO4)2/2] interconnected via the ReO4− ligands. The chains are held together in the solid by hydrogen bonding. The compound is paramagnetic and follows the Curie–Weiss law with a magnetic moment of 4.0μB at room temperature and θ=−42K. It loses hydration water in two steps at temperatures below 400K; decomposition begins at 850K, forming Yb2O3(Re2O7)2 and is complete at 1350K leading to Yb2O3 as final product.