The design and construction of high‐power nitrogen 3371 Å laser is described in detail. The laser produces 13 mJ at 3371 Å in a 12 nsec FWHM pulse at a repetition rate of 5 pulses per second. Various models of the laser have yielded 108pulses with very infrequent component failure. When a second mirror is added, strong laser action is observed in the N2first positive system; the total resultant ir output energy is about 3 mJ in a 50 nsec FWHM pulse.