  We compute the matrix elements of the operators which contribute to spectator
effects in inclusive decays of $B$-mesons. The results agree well with
estimates based on the vacuum saturation (factorization) hypothesis. For the
ratio of lifetimes of charged and neutral mesons we find
$\tau(B^-)/\tau(B_d)=1.03\pm 0.02\pm 0.03$, where the first error represents
the uncertainty in our evaluation of the matrix elements, and the second is an
estimate of the uncertainty due to the fact that the Wilson coefficient
functions have only been evaluated at tree-level in perturbation theory. This
result is in agreement with the experimental measurement. We also discuss the
implications of our results for the semileptonic branching ratio and the charm
yield.
