  We study the semileptonic decays B -> Xs e+ e- and B -> Xs mu+ mu- in generic
supersymmetric extensions of the Standard Model. SUSY effects are parameterized
using the mass insertion approximation formalism and differences with the
Constrained MSSM results are pointed out. Constraints on SUSY contributions
coming from other processes (e.g. b -> s photon) are taken into account.
Chargino and gluino contributions to photon and Z-mediated decays are computed
and non-perturbative corrections are considered. We find that the integrated
branching ratios and the asymmetries can be strongly modified. Moreover, the
behavior of the differential Forward-Backward asymmetry remarkably changes with
respect to the Standard Model expectation.
