Spin-lattice relaxation times were measured for the N-14 relaxation of both N-14 nuclei in NNO in the pure gas and in mixtures with the following buffer gases; Ar, Kr, Xe, HCl, N-2, CO, CO2, CH4, CF4, and SF6. Effective collision cross sections for molecular reorientation of NNO in collisions with these ten molecules are obtained, as a function of temperature, directly from the measured relaxation times of the end N-14 nucleus in the NNO molecule.