When mixts. of O3 and mol. H2 were flashed in a laser cavity, stimulated ir emission at 3050-3410 cm-1 was detected, and the radiation was identified as the P1 transitions of the v = 3 -> 2, 2 -> 1, and 1 -> 0 fundamentals of the OH radical. Stimulated emission was obsd. with flash energies of 400-2000 J, for O3/H2 mixts. at relative partial pressures of 1:10 and total pressures of 1-10 torr. Addn. of 70 torr of He did not affect the laser emission; no stimulated emission was obsd. in the presence of 70 torr of mol. N2.