The rate of secondary charm-quark-pair production has been measured in 4.4
million hadronic Z(0) decays collected by OPAL. By selecting events with th
ree jets and tagging charmed hadrons in tie gluon jet candidate using lepto
ns and D*+/- mesons, the average number of secondary charm-quark pairs per
hadronic event is found to be (3.20+/-0.21+/-0.38) x 10(-2).