Blue up-conversion luminescence properties in Tm3+-doped lead chloride tellurite glasses have been studied under 980nm excitation. The intense blue and relatively weak red emissions centered at 476 and 649nm corresponding to the transitions 1G4 → 3H6 and 1G4 → 3H4 of Tm3+, respectively, are simultaneously observed at room temperature. The effect of PbCl2 on up-conversion intensity is observed and discussed, and possible up-conversion mechanisms are evaluated. The intense blue up-conversion luminescence of Tm3+-doped lead chloride tellurite glasses may be a potentially useful material for developing up-conversion optical devices.