Study of Charm Production in W Decays Chazelle G Giehl I Henrard P 1997 The production rate of charm quark in W decays has been measured at LEP-2 energies with the ALEPH detector. The charm quarks are tagged by using an algorithm based on the kinematic properties of the jets, the number of identified leptons, the energy of fully reconstructed D mesons and on lifetime information. PREPRINT