  We quantify the ability of B-Factories to observe supersymmetric
contributions to the rare decays B -> X_s \gamma and B -> X_s l+ l-. A global
fit to the Wilson coefficients which contribute to these decays is performed
from Monte Carlo generated data on B(B -> X_s \gamma) and the kinematic
distributions associated with the final state lepton pair in B -> X_s l+ l-.
This fit is then compared to supersymmetric predictions. Evaluation of the
Wilson coefficients is carried out with several different patterns of the
superpartner spectrum. We find that the B-Factories will be able to probe
regions of the SUSY parameter space not accessible to LEPII, the Tevatron, and
perhaps the LHC. We also employ the recent NLO calculation of the matrix
elements for B -> X_s \gamma and find the bound mH+ > 300 GeV in
two-Higgs-doublet models using present data.
