The operating characteristics of a Nd:GYSGG laser in the 1.3 µm wavelength band based on the transition 4 F 3/2 → 4 I 13/2 is demonstrated. Using two different output couplers, single wavelengths operation at 1336 nm and dual-wavelength operation at 1321/1336 nm are obtained. The 1329 nm laser spectrum is also found when the pump level is relatively weak. The stimulated emission cross section of the 1336 nm laser line is estimated to be 1.12 time of that of the 1321 nm laser line. The output power of 1.98 W at 1336 nm is achieved with the pump power of 13.5 W, corresponding to the conversion efficiency of 14.7%. This is the first report on a 1.3-µm Nd:GYSGG laser to our knowledge.