Electron Paramagnetic Resonance (EPR) spectrum of pairs of two identical rare earth ions is considered in the case where the two ions feel slightly different crystal fields giving different g factors. When the differences Deltag between the g factors give a Zeeman difference term DeltagbetaB(0) of the order of magnitude of the interaction between the two ions, the pair spectrum is composed of four lines instead of two: the usual doublet structure, and two additional satellites around the main central transitions. It is shown that for rare earth ions, the shape of the EPR pair spectrum is very sensitive to small g factor differences. This situation is illustrated by the case of neodymium pairs in the SrA(12)O(19) host. (C) 2003 Elsevier B.V. All rights reserved.