We report DC magnetization and electron paramagnetic resonance (EPR) measurements in ceramic samples of La0.67Ca0.33Mn1-yCryO3 (0 less than or equal to y less than or equal to 0.1). We have observed a decrease of T-C with doping, which reveals a continuous dilution of the ferromagnetic exchange interaction. On the other hand, although the EPR linewidth (Delta H-pp) depends on the doping level, its high-temperature limit value (Delta H-pp(infinity)) remains constant around 0.25 T. This implies that dynamic double exchange (DE) interaction is too slow to contribute to the exchange narrowing process. (C) 2000 Elsevier Science B.V. All rights reserved.