An experimental condition has been found for the CO chemical laser where it would appear that vibration‐vibration relaxation processes (V‐V) compete with stimulated emission to force the laser to operate in essentially a single line &ngr; = 10–9,P(17). No frequency‐selective element has been used in the laser cavity. Experimental data and results of computations on a laser model are presented to support this suggestion. A cw power of 7 W has also been achieved in this longitudinal flow system with the addition of cold CO (300 °K) for the chemical efficiency of ∼ 3.2%, one of the highest values for any system reported at the present time.