The random exchange potential at the interfaces between magnetic and nonmagnetic layers is proposed to be an origin of the giant magnetoresistance in the metallic superlattices. The material dependence of the magnetoresistance is studied for Fe/TM and TM/Cu superlattices, where TM are the 3d-transition metal elements. The calculated results are consistent with the experimental ones. Some possible combinations of materials which may show large magnetoresistance are predicted.