Rate constants for collisional detachment of NO-, NO- + X → NO + X + e, have been measured from 193 to 506°K for X as He, Ne, H2, NO, CO, CO2, N2O, and NH3. The data fit Arrhenius plots kd=Ae-E/kT with both A and E showing large variations with X. From equilibrium constant considerations, electron attachment rates to NO have been calculated. An estimate for the electron affinity of NO3 is obtained from some auxiliary considerations. Rate constants for the charge-transfer reactions of NO- with O2 and NO2 were found to be 5 and 7.4 × 10-10 cm3sec-1, respectively.