N-tert-Butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)]nitroxide (DEPN) as P-phosphonylated nitroxide was prepared using tert-butylamine, pivalaldehyde and phosphonic acid diethyl ether as starting materials. This nitroxide revealed a reversible redox peak in cyclic voltammetry at + 0.81 V versus Ag/AgCl, and showed electrocatalysis for the oxidation of alcohol. A preparative electrocatalytic oxidation of 4-methylbenzyl alcohol on the nitroxide yielded 98% 4-methylbenzaldehyde by 10 h of electrolysis. The current efficiency, turnover number and pseudo-first-order kinetic constant of the reaction were 96.5%, 39 and 0.95 x 10 s(-1), respectively.