We report ESR measurements in UBe13 doped with 1000 ppm Gd, at temperatures down to 0.4 K, which is well below the superconducting transition temperature of this heavy fermion system. Our most important result is the observation that, within the experimental error, the Knight shift of the local Gd moments does not decrease below the normal-state value. The possible implications of this result for the nature of the superconductivity are discussed. © 1986.