  The renormalization factors of the dimension-six effective operators for
proton decay are evaluated at two-loop level in the supersymmetric grand
unified theories. For this purpose, we use the previous results in which the
quantum corrections to the effective Kahler potential are evaluated at
two-loop level. Numerical values for the factors are presented in the case of
the minimal supersymmetric SU(5) grand unified model. We also derive a simple
formula for the one-loop renormalization factors for any higher-dimensional
operators in the Kahler potential, assuming that they are induced by the gauge
interactions.
