High quality Yb3+ and Er3+ co-doped Gd3Sc2Ga3O12 (Yb,Er:GSGG) crystals were grown by the Czochralski (Cz) method, and their absorption and fluorescence properties with the gamma-ray radiation have been investigated. In comparison with Er:YAG crystals, these co-doped crystals exhibit much less color-center absorption after the illumination of gamma-ray. Excited by 940 nm LD, two of the strongest fluorescence peaks were observed near 2.7 and 2.8 pm, suggesting that the Yb3+ can act as a sensitizer for Er3+ ion in Yb,Er:GSGG crystals. In particular, the fluorescence intensity of these crystals does not deteriorate by the radiation of gamma-ray even with a dose of 100 Mrad, indicating that Yb,Er:GSGG possesses high capability for enduring the gamma radiation and is a potential laser gain medium for being used under radiant environment. (C) 2010 Elsevier B.V. All rights reserved.