Direct nuclear pumping of a low‐temperature (≊150 K)3He‐CO laser has been achieved using the volumetric3He(n,p)3H nuclear reaction. Lasing occurred on the vibrational bands of CO at ≊5 &mgr;. Effects of N2on the system were investigated, as well as scaling of laser output with CO concentration, thermal neutron flux, and total pressure. This is the first volume‐pumped, nuclear powered CO laser.