In the present work, we report ab-initio studies of the magnetic property variations with pressure of both iron sites in the structure of Fe4N, using full-potential linearized augmented plane wave method and the Perdew-Burke-Ernzerhof functional and generalized gradient approximation to describe the exchange-correlation potential are reported. The results show that the magnetic moment of FeI is almost constant while the magnetic moment of FeII presents a discontinuity when the lattice parameter is varied. This is reflected in the compression of the spin up and down energy bands to different concentration points. The variation in the FeII magnetization arises mainly from changes in the dxy, dxz, dyz and dx2-y2 orbitals. © 2009 Elsevier B.V. All rights reserved.