Subsolidus phase relations in the ternary system Y2O3-Eu2O3-SnO2 have been investigated by means of X-ray powder diffraction. The samples are prepared by solid-state chemical reaction. The (Y1-xEux)2Sn2O7 and (Y1-xEux)2O3 binary systems form complete solid solutions with pyrochlore-type and cubic structures, respectively. The characteristic photoluminescence peaks observed from (Y1-xEux)2Sn2O７ and (Y1-xEux)2O3 compounds correspond to Eu3+ intra-4fn shell transitions. The difference between the emission and excitation spectra of (Y1-xEux)2Sn2O7 and (Y1-xEux)2O3 can be explained by considering the surroundings of crystallographic site occupied by Eu3+. Y2O3-Eu2O3-SnO2 ternary s