  It is analyzed the branching ratio $B(b\rightarrow s\gamma)$ in the context
of minimal $N=1$ supergravity with radiatively broken electroweak symmetry
group. There is a strong dependence on supersymetric parameters, but
constraints on the charged Higgs mass in non-supersymmetric models are relaxed,
due to large contribution from the chargino/up-type squark sector that
interacts destructively with the Standard Model and the charged Higgs
contributions. Large suppressions/enhancements of the branching fraction are
found for large values of $\tan\beta$.
