- X-band electron magnetic-resonance (EMR) measurements of polycrystalline CaMn1−yMoyO3 (0⩽y⩽0.14) samples were performed at 120K⩽T⩽540K. The data obtained are compared with those of another electron-doped manganite system, CaMn1−xRuxO3 (0⩽x⩽0.40). The observed anomalies of the EMR parameters correlate pretty well with the temperatures of antiferro-, ferromagneticlike, and orbital/charge-ordering transitions in these systems. However, a strong difference is observed between the resonant properties of Mo- and Ru doped series at both paramagnetic (PM) and magnetically ordered states. To describe such a difference, the energy-band diagrams, which comprise the deep impurity t2g-like states +eg-like conductive band for CaMn1−xRuxO3 and shallow impurity states+conductive band, both having eg-like symmetry, for CaMn1−yMoyO3, are proposed. Specific electrons’ contribution to the EMR linewidth at PM temperatures is introduced for the considered systems.