The structure of yttrium-decavanadate-24-hydrate, [Y₂V₁₀O₂₈·24H₂O], was determined by neutron diffraction at temperatures of 297 and 60 K. Space group P-1, triclinic, Z = 2; at 297 K : a = 9.36(1), b = 9.86(1), c = 23.53(3) Å, α = 98.79(2), β = 98.15(2), γ = 89.30(2), V = 2123(5); at 60 K : a = 9.19(3), b = 9.85(3), c = 23.31(12) A, α = 99.03(3), β = 98.99(6), γ = 89.39(6)°, V = 2058(13). Final R factors of 10 and 9.4% were obtained using 1955 and 1100 observed structure factors at both temperatures, respectively. The position of the 24 water molecules was determined and the characteristics of the hydrogen bonds were analyzed at both temperatures.