LEP measurements of V$_{cb}$ and V$_{ub}$

The magnitude of the CKM matrix element V/sub cb/ has been measured using B/sup 0/ to D*/sup +/l/sup -/ nu decays recorded on the Z/sup 0 / peak using the OPAL, ALEPH and DELPHI detectors at LEP. The D*/sup +/ to D/sup 0/ pi /sup +/ decays were reconstructed both in particular decay modes and via an inclusive technique. The product of V/sub cb/and the decay form factor of the B/sup 0/ to D*/sup +/l /sup -/ nu transition at zero recoil F(1) was measured to be F(1) V /sub cb/=(35.6+or-1.7)*10/sup -3/. V/sub cb/ is obtained by using Heavy Quark Effective Theory calculations for F(1). The semi-leptonic branching ratio BR(b to cl nu ) is also used to extract V/sub cb/. The combined result is V/sub cb/=(40.7+or-1.9)*10/sup -3/. The semi-leptonic branching ratio BR(b to ul nu ) is measured and used to extract the magnitude of V/sub ub/, V/sub ub/=(4.09/sub -0.69//sup +0.59/)*10/sup -3/. (12 refs).