Radiolysis of nitrobenzene shows that most of the radiolytic products can be related structurally to the parent molecule. Of the gaseous products, nitrogen is the most important. Other gaseous products are hydrogen, nitric oxide, carbon monoxide, and carbon dioxide. Major products are phenol, nitrosobenzene, and the isomeric nitrobiphenyls. Lesser products are benzene, biphenyl, the isomeric dinitrobenzenes, and the isomeric dinitrobiphenyls. The effects of the additives, diphenylpicrylhydrazyl, galvinoxyl, and sulfur hexafluoride, on the yields of nitrogen, nitric oxide, hydrogen, nitrosobenzene, and phenol were determined. The results with the additives are complicated and do not lend themselves to a simple interpretation.