A peculiar mechanism of light absorption and emission related to the 3d-electron states in iron group atoms occurs in the dilute magnetic semiconductors (DMSs) along with the conventional band-to-band mechanism. The light emission from 3d-levels is important for electroluminescence applications. We have studied DMS Cd1-xMnxTe and Cd1-x-yMnxMgyTe wherein the bright 3d-luminescence band near 2 eV is observed for (x + y) > 0.4. A saturation of 3d-luminescence intensity J(L) is found to occur at a low excitation level J(ex) when only a minor portion of manganese ions is excited. The saturation of the 3d-luminescence is more readily achieved in Cd1-xMnxTe for x > 0.5 when the temperature rises from 4 up to 77 K. The energy position of 3d-luminescence band in Cd1-x-yMnxMgyTe depends weakly on the Mn and Cd relative concentrations, the value of y being fixed, but it shifts significantly towards higher energy with increasing value of y. Thus the incorporation of Mg contributes strongly to the inhomogeneous broadening and suppresses a Frenkel exciton migration via Mn2+ ions. This result is consistent with the decrease of saturation for Cd1-x-yMnxMgyTe as compared to Cd1-xMnxTe. The luminescence decay becomes faster with the increasing J(ex) due to the initiation of the nonradiative relaxation. The temperature and concentration dependences of J(L) point out the importance of energy transfer between Mn2+ ions. The luminescence decay becomes faster with the increasing J(ex) due to the initiation of the nonradiative relaxation. It turns out that for Cd0.6Mn0.4Te wherein the 3d-luminescence excitation threshold coincides with band-to-band Wannier exciton energy, the dependence of the 3d-luminescence intensity upon J,, shows a peculiarity.