Based on the phenomenological theory of Camley and Barnas and coworkers (C-B), the dependence of magnetoresistance in Fe/Cr multilayers on the applied magne-tic field is calculated. In these multilayers an antiferromagnetic coupling exists between any two adjacent Fe-layers. The applied magnetic field is either parallel or perpendicular to the layers. Good agreement of the calculated results with the experimental ones is found. The symmetry implicitly involved in the C-B theory is disclosed and is used to simplify the original C-B formalism, this leads to the closed expressions for the distribution function of conducting electrons and for magnetore-sistance.