Magnetic and electronic properties of Cr(0 0 1) thin films and transition metal monolayer (TM = Ti, V, Cr, Mn, Fe, Co, and Ni) on Cr(0 0 1) substrate are reported and discussed within the framework of first principle method based on density functional theory (DFT). In our calculations, we have considered two possible spin orientations leading to ferromagnetic (FM) and antiferromagnetic (AFM) coupling. The surface energy of Cr(0 0 1) is given and compared to experimental 4d metals values. Also, total and formation energies, total and local magnetic moments of TM/Cr(0 0 1) are determined for both ferromagnetic and antiferromagnetic configurations and compared to other works. Thus, Cr layers in Cr(0 0 1) thin films remain antiferromagnetically coupled, as in bulk Cr or Cr-2 molecule. The same behavior is found for Ti, V, and Cr in TM/Cr(0 0 1), quite the opposite, Mn, Fe, Co, and Ni prefer to be ferromagnetically coupled to Cr subsurface layer, and only Mn and Fe in the ferromagnetic coupling have induced a spin-switch in all Cr layers. We have also reported the polarized densities of states of each layer in the ground state of TM/Cr(0 0 1) systems, showing the same behavior as concluded from energy and magnetic results. (C) 2002 Elsevier Science B.V. All rights reserved.