Several rare earth activators (Dy3+, Sm3+, Eu3+) doped nanocrystalline and microcrystalline Sr2GdxY7,9-x(SiO4)(6)O-2 are synthetized by sol-gel method. The luminescence and the energy transfer propel-ties from Gd3+ to Ln(3+) are studied. The results show that the energy transfer efficiency from Gd3+ to Ln(3+) is in the sequence Sm3+ < Eu3+ < Dy3+ in the nanocrystals, in the microcrystals the sequence is different, and compared to the counter microcrystals, the value of energy transfer efficiency in the nanocrystals from Gd3+ to Ln3+ is lower. (C) 2003 Published by Elsevier B.V.