  We review the available constraints on the low energy supersymmetry. The bulk
of the electroweak data is well screened from supersymmetric loop effects, due
to the structure of the theory, even with superpartners generically light,
${\cal O}(M_Z)$. The only exception are the left-handed squarks of the third
generation which have to be $\simgt {\cal O}(300$ GeV) to maintain the success
of the SM in describing the precision data. The other superpartners can still
be light, at their present experimental mass limits. As an application of the
derived constraints (supplemented by the requirement of ``naturalness'') we
discuss the predictions for the mass of the lighter MSSM Higgs boson in
specific scanarios of supersymmetry breaking.
