A CO TEA laser, cooled to 77°K by a surrounding liquid‐nitrogen bath, is found to exhibit laser action on approximately 60 transitions over the spectral range 4.960–5.610 &mgr;m. Following a single 0.5‐&mgr;sec excitation pulse, lasing action is observed to continue up to 2 msec with 15 Torr of CO and up to 4 msec with a 14‐Torr CO&sngbnd;N2mixture.