Ce3+ and/or Eu2+ doped Ca2AlSi3O2N5(CASON) phosphors are synthesized via solid state reaction under NH3 atmosphere, and the effects of Ce3+ doping on the Eu2+ emission are studied in detail. The Ce3+ activated sample exhibits intense blue emission under 270-350 nm excitation, while the Eu2+ activated sample exhibits intense green emission band which peaked at about 500 nm under 310-360 nm excitation.The energy transfer from Ce3+ to Eu2+ in the co-doped samples has been confirmed by the analysis of intensity and decay time for both Ce3+ and Eu2+ emissions. The incorporation of 0.7 mol% Ce3+ to CASON:0.5 mol% Eu2+ significantly increases the emission intensity by similar to 45% of the original value. The energy transfer is demonstrated to be a resonant type via a dipole-dipole mechanism and the critical distance of Ce3+-Eu2+ has been also calculated to be about 23.6 angstrom. (C) 2014 Elsevier Ltd. All rights reserved.