Polycrystalline zircon-type dysprosium orthovanadate, DyVO 4, prepared from a single crystal grown by slow cooling from PbO/PbF 2 flux, was studied by X-ray diffraction. Rietveld refinement provided the following unit cell size and oxygen atom coordinates: a = 7.14811(4) Å; c = 6.30825(4) Å, V = 322.323(3) Å3, y(O 2-) = 0:4300(4); z(O 2-) = 0.2082(4) which are of a particularly high accuracy and show consistency with earlier reported values. Density functional theory calculations within the generalized gradient approximation for the exchange-correlation energy were also performed, providing values of structure parameters which differ by less than 2% from the experimental ones. The agreement between theory and experiment demonstrates the value of these calculations for understanding the structure of compounds of RVO 4 family. In addition, density functional theory calculations were performed for the scheelite-type DyVO 4; also for this polymorph the discrepancy with the only known set of lattice parameters is less than 2%. Values of oxygen atom coordinates have not been reported yet for this polymorph; here, the calculated ones are quoted.