From an analysis of inclusive leptons in data collected by the ALEPH detector at LEP, we measure the fractions of b and c events in hadronic Z decays. The b fraction times semileptonic branching ratio is measured to be . Assuming a b semileptonic branching ratio of 0.102 ± 0.010 gives , in good agreement with the standard model prediction of 0.217. The c fraction times semileptonic branching ratio is measured to be . Assuming a c semileptonic branching ratio of 0.090 ± 0.013 gives , in agreement with the standard model prediction of 0.171.