  The gluino-induced contribution to the decay $b \to s \gamma$ is investigated
in supersymmetric frameworks with generic sources of flavour violation. It is
emphasized that the operator basis of the standard model effective Hamiltonian
is enlarged and that a suitable redefinition allows to realize the usual scheme
of leading and next-to-leading logarithmic contributions when QCD corrections
are included. The effects of the leading order
  QCD corrections on the inclusive branching ratio for $b \to s \gamma$ are
shown. Constraints on supersymmetric sources of flavour violation are derived.
