Infrared spectra and lifetimes of 4 I 13/2 state of Er 3+ in tungsten–tellurite glasses doped with different concentrations of Er 2 O 3 were measured and studied. Judd–Ofelt analysis on absorption spectra was performed. The lifetime of the 4 I 13/2 state decreases with the increase of the Er 3+ concentration due to energy transfer processes. The energy transfer coefficient of 1.6×10 −18 cm 3 s −1 was obtained. It is observed that the nonradiative relaxation rate of 4 I 11/2 – 4 I 13/2 transition of Er 3+ in tungsten–tellurite glass is unchanged with the increase of Er 3+ concentration, and about twice as that in TeO 2 –ZnO–Na 2 O glass.