Di-tert-butyl ketoxime has been prepared by a new and simple procedure. It can be oxidized by a variety of oxidizing agents to a moderately stable free radical, di-tert-butyliminoxy (1), a blue liquid, fp -21°. Some of the physical and chemical properties of 1 have been determined. It dimerizes slowly and irreversibly at room temperature, 2kt = 2.1 × 10-5 M-1 sec-1 in benzene at 24°. Di-tert-butylnitrimine is formed by reaction of 1 with nitric oxide. Hydrogen is abstracted by 1 from a variety of organic materials including phenols, triethylamine, triethyl phosphite, hydrazine, hydrazobenzene, 1,4-cyclohexadiene, toluene, ethylbenzene, cumene, and hydroxylamines. Kinetic studies have been made on some of these reactions.