The mixed rare earth oxide (Dy 1-x Er x ) 2 O 3 (0.0 β€ x β€ 1.0) were synthesized by a sol-gel process. X-ray and neutron diffraction data were collected and crystal structure and microstructure analyses were performed using Rietveld refinement method. All samples were found to have the same crystal structure and formed solid solutions over the whole range of x. Preferential cationic distribution is found for all samples but with different extent with Dy 3+ preferring the 8b among the two non-equivalent sites 8b and 24d of the space group Ia3. The lattice parameter is found to vary linearly with the composition x and a systematic variation is found in the r.m.s microstrain 2 1/2 L Ξ΅ β© βͺ . Magnetization measurements were done in the temperature range 5-300 K and a behavior in accordance with Curie-Weiss law was found. Anomalous concentration dependence is found in magnetic susceptibility which is ascribed to the concentration dependence of effective crystal field combined with the contribution of 4 I 15/2 and 6 H 15/2 manifold at elevated temperature. The effective magnetic moments ΞΌ eff is found to decrease linearly with composition parameter x, except for sample x=0.5 where the magnetization is enhanced. The Curie-Weiss paramagnetic temperatures indicated antiferromagnetic interaction. These magnetic results are discussed in view of the cationic distribution.