We compute quadratically divergent supergravity one-loop effects on soft supersymmetry-breaking parameters and the mu term in generic hidden sector supergravity models. These effects can significantly modify the matching condition for soft parameters at the Planck scale and also provide several new sources of the mu, term which are naturally of order the weak scale. We also discuss some phenomenological implications of these effects, particularly the violation of the scalar mass universality which may lead to dangerous flavor changing neutral current phenomena, and apply the results to some familiar supergravity models as well as superstring effective supergravity models.