Radiative corrections to Higgs masses in Z' models

We calculate radiative corrections to the masses of the Higgs bosons in a minimal supersymmetrical model that contains an additional non-anomalous U(1)' gauge symmetry. With some fine-tuning of the U(1)' charges of the Higgs fields, it is possible to suppress the Z-Z' mixing. We use this fact, along with the lower bound on the lightest Higgs mass after LEP II era, as a criterion to restrict the set of parameters in our analysis. We calculate the mass of the lightest Higgs and its mixing with the other Higgs bosons in a large region of the parameter space.