We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt decays using the data sample corresponding to an integrated luminosity of 5.6  fb−1 of pp collisions at Tevatron with s√=1.96  TeV, collected with the CDF II detector. We construct templates of two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decays in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop=172.1±1.1(stat)±0.9(syst)  GeV/c2.