Fluorescence emissions at both 1.31 and 1.55 mu m communication windows were observed from Pr3+/Er3+ codoped Ge-As-Ga-S glasses with a single wavelength pumping at 986 nm. The lifetime of the Er3+:I-4(11/2) level decreased as the Pr3+ concentration increased, and that of the Pr3+:(1)G(4) level increased as the Er3+ concentration increased. Energy transfer from the Er3+:I-4(11/2) level to the Pr3+:(1)G(4) level was responsible for emission of the 1.31 mu m fluorescence from the Pr3+:(1)G(4) level. Ge As-Ga-S glasses that have been doped with Pr3+ and Er3+ cations are promising amplifier materials for both 1.31 and 1.55 mu m communication windows.