Electron paramagnetic resonance (EPR) experiments were performed on a Pb 1− x Ce x Se crystal at liquid-helium temperatures and show very clearly that the doublet Γ 7 is the ground state for cerium ions. The cubic symmetry is shown and the effective Landé factor for the Ce 3+ is determined to be 1.354±0.003. An orbital reduction factor is introduced to explain the g experimental value. High-field magnetization results are in good agreement with the EPR results. The nominal Ce composition in PbSe deduced from saturation of the magnetization, x= 0.0405±0. 0 0 0 3, is very closed to the value determined by microprobe analysis (x= 0.04). At 1.5 K, an antiferromagnetic interaction between the nearest-neighbor cerium atoms is found, J ex/k B=− 0.715 K. The low-field magnetic-susceptibility results show that the magnetic moment of cerium impurities is strongly temperature dependent, explained by the presence of the crystal-field effect and the Kondo effect.