A new uranium(IV) fluorooxalate, UF3(H2O)(C2O4)(0.5), has been synthesized by a hydrothermal method and structurally characterized by single-crystal X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The structure consists of two-dimensional layers of corner- and edge-sharing tricapped trigonal prisms with the composition UF4/2F2/2O3 linked by bisbidentate oxalate ligands to form a three-dimensional framework. Magnetic susceptibilities were measured to confirm the tetravalent state of uranium. Crystal data: monoclinic, space group C2/c, a = 17.246(3) angstrom, b = 6.088(1) angstrom, c = 8.589(2) angstrom, beta = 95.43(3)degrees, and Z= 8.