Some characteristics of CO laser operation are reported. A discussion of the roles of the various ingredients necessary for optimization of the gas compositions is given and measurements of efficiency, spectral output, small signal gains, and saturation intensity at various temperatures are reported. Important mechanisms that dominate the kinetics of the molecules and electrons in electrical discharge systems are described briefly. Several experimental observations are presented to support the interpretations and conclusions that have been drawn regarding the pumping processes and optimum operating characteristics. The possibility of high-power operation of the CO laser with high efficiency is demonstrated by the attainment of laser efficiencies up to 47 percent with small signal gain coefficients of nearly 0.5 percent/cm and a saturation intensity of 15 W/cm2at a gas temperature of 200°K.