CaLa2(MoO4)(4):Sm3+,Eu3+ phosphors are prepared using a convenient solid-state reaction route. The red emission intensity of Eu3+ is enhanced by Sm3+ ion codoping. The energy transfer mechanism from Sm3+ to Eu3+ was found to be a dipole-quadrupole interaction with a critical distance of 10.42 angstrom. With increasing Eu3+ doping content, the energy transfer efficiency (Sm3+ -> Eu3+) gradually increased to 75.5%. The thermal quenching behavior was investigated using absorption and emission spectra. The thermal quenching temperature (T-50) of CaLa2(MoO4)(4):Sm3+,Eu3+ phosphors is above 200 degrees C, and the activation energy of the thermal quenching process is 0.13 eV. The effect of codoped Sm3+ ions on the thermal stability of CaLa2(MoO4)(4):Sm3+,Eu3+ phosphors is investigated. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3518782] All rights reserved.