We describe the preparation, crystal structure determination and magnetic properties of a new series of ordered double perovskite oxides Sr(2)LnMoO(6) (Ln = Eu, Gd, Dy, Ho, Er, Yb) with Mo5+ and Ln(3+) electronic configurations. These compounds have been obtained by solid state reaction under reducing conditions in order to stabilize Mo5+ cations. Structural characterization by XRPD and NPD was performed when Ln = Ho, Er, Yb and just XRPD for absorbing Ln = Eu, Gd, Dy. At room temperature, an excellent Rietveld fit was obtained for all the samples in a monoclinic symmetry, space group P2(1)/n, with long-range ordering of Ln and Mo atoms. Magnetic susceptibility measurements show that some of these materials present magnetic ordering below 25 K and the determined effective magnetic moments are consistent with those expected for the pair Le(3+)-Mo5+. All the phases have negative values of the Weiss temperature indicating dominance of antiferromagnetic interactions. (C) 2015 Elsevier Ltd. All rights reserved.