Two new vanadium(III) phosphates have been synthesized hydrothermally and characterized structurally by Rietveld refinement of X-ray powder diffraction data. The first, VPO4.H2O, is monoclinic with a = 6.6953(2) angstrom, b = 7.7925(3) angstrom, c = 7.3504(2) angstrom, and beta = 11 5.255(1)degrees. The structure was refined in space group C2/c (No. 15). The compound is isostructural with one form of NiSO4.H2O and MnPO4.H2O and closely related to a large class of hydrated divalent metal sulfates with the structure of the mineral kiesserite, MgSO4.H2O. The magnetic susceptibility data show Curie-Weiss behavior down to 5 K and are consistent with the presence of all of the vanadium atoms in the trivalent state. The other vanadium(III) phosphate, V1.23(PO4)(OH)0.69(H2O)0.31.0.33H2O, is tetragonal with a = 5.1811(1) angstrom and c = 12.9329(4) angstrom. The structure was refined in space group I4(1)/amd (No.141). The compound is isostructural with the Mineral caminite, Mg(SO4).xMg(OH)2.(1 - 2x)H2O, and has magnetic susceptibility behavior indicating strong antiferromagnetic coupling.