Taking into account the quantum size effects and considering three types of scattering from bulk impurities, rough surfaces, and rough interfaces, we use the quantum-statistical Green's function approach and Kubo theory to calculate the giant magnetoresistance (GMR) in magnetic multilayered structures. Our calculation can reproduce the main features of GMR experiments, including the oscillations of GMR with nonmagnetic thickness, and the GMR increases with increasing number of bilayers N of the (Fe/Cr)(N)/Fe system and others. As well, the question whether or not the scattering rates due to the impurities, surfaces, and interfaces add up is also addressed to. (C) 1999 Published by Elsevier Science B.V. All rights reserved.