Fibers doped with rare-earth constituents such as Yb3+ and Er3+, as well as fibers co-doped with these species, form an essential part of many optical systems requiring amplification. This study consists of two separate investigations examining the effects of gamma-radiation-induced photodarkening on the behavior of rare-earth doped fibers. In one part of this study, a suite of previously irradiated rare-earth doped fibers was heated to an elevated temperature of 300°C and the transmittance monitored over an 8-hour period. Transmittance recoveries of ~10 - 20% were found for Er3+- doped fiber, while recoveries of ~5 - 15% and ~20% were found for Yb3+- and Yb3+/Er3+ co-doped fibers, respectively. In the other part of this study, an Yb3+-doped fiber was actively pumped by a laser diode during a gamma-radiation exposure to simulate the operation of an optical amplifier in a radiation environment. The response of the amplified signal was observed and monitored over time. A significant decrease in amplifier output was observed to result from the gamma-radiation exposure.