The voltage‐current dependence is investigated for pulsed self‐sustained uniform‐glow discharges by using commerical‐grade mixtures of CO2, N2, and He at near‐atmospheric pressures. For a given mixture, the discharge is found to stablize at a value ofE/Nwhich is independent of discharge current density, total pressure, and electrode spacing;Eis the electric field andNis the number density of the gas. We interpret these observations as evidence that the glow condition is effectively controlled by attachment to CO2and also to H2O, a gaseous impurity. Calculations of theE/Ncharacteristic, based on a model which includes recombination and attachment losses, are in agreement with experimental results for all mixtures studied.