  We discuss the large radiative corrections to the masses of supersymmetric
Higgs bosons in the MSSM and in its simplest extension, the NMSSM, with
particular attention paid to the bounds on the lightest CP-even Higgs mass
found in both models. In the case of the MSSM, these corrections are found to
be primarily associated with the effects top quark and stop squark loops, while
for extended models they also include significant contributions from Higgs and
Higgsino loops. (Talk presented at SUSY-93, Boston, March 1993)
