Gain and saturation are investigated in a kW CO2&sngbnd;N2&sngbnd;He gas‐transport laser. The active medium flows at 35 m/sec transverse to the probe laser beam. Gain falls exponentially downstream of the excitation region with a characteristic decay distance of 7 cm, giving a decay time of approximately 2 msec. A saturation parameter of approximately 250 W cm2is determined. This large value is due to rapid flow which sweeps the molecules through the laser beam in a time shorter than the upper state relaxation time.