The internal state distribution of the HNO product from the O(3P) + NH2 reaction was derived in a crossed beam experiment. Rotational state distributions in the K(a) = 0 and 1 manifolds of the ground (000) HNO vibronic level were derived from laser fluorescence excitation spectra. The HNO rotational state distribution was found to be very cold. This reaction product can be formed by decomposition of H2NO and HNOH intermediate. The low degree of energy disposal in HNO internal excitation provides evidence for a barrier (in excess of the endoergicity) for formation of HNO + H from these intermediates, as has been predicted from quantum chemical calculations and a RRK analysis on this reaction.