Natural conduction in nitrobenzene has been measured in electric fields of 50-50 000 V cm−1, over a temperature range of 0-200°C using brass and stainless-steel electrodes. The electrode materials, dissolved air and degree of purification are observed to have a pronounced influence on the conductivity. The cathode appears to be the most likely source of electrons and conduction occurs as a result of the hopping process. The thermal activation energy in nitrobenzene is found to be 0·53±0·05 ev.