Estimates of lifetimes and partial branching ratios for the baryons $Ξ_{bc}^{+}$ and $Ξ_{bc}^{0}$ are presented using the inverse heavy quark mass expansion technique carried out in the Operator Product Expansion approach. We take into account both the perturbative QCD corrections to the spectator contributions and, depending on the quark contents of hadrons, the Pauli interference and weak scattering effects between the constituents, using a potential model for the evaluation of the non-perturbative parameters.

15 pages, LATEX file, 2 eps-figures