  We analyze the FCNC semileptonic decay $B \to X_s l^+l^-$ in a fully
left-right supersymmetric model. We give explicit expressions for all the
amplitudes involved in the process, and compare the numerical results with
experimental bounds, in both the constrained case (where the only flavor
violation comes from the Cabibbo-Kobayashi-Maskawa matrix) and the
unconstrained case (including soft breaking supersymmetry terms). Stringent
constraints on the parameter space of the model are obtained. We also include
constraints from $b \to s \gamma$.
