The electrocatalytic properties of a N2 incorporated diamond nanowire (N-DNW) unmodified electrode towards the oxidation of nicotinamide adenine dinucleotide (NADH) was critically evaluated. The electrochemical behavior of the N-DNW unmodified electrode was examined and compared with that of boron-doped diamond, glassy carbon electrode, and graphite electrodes. The N-DNW electrode had high selectivity and high sensitivity for the differential pulse voltammetric detection of NADH in the presence of ascorbic acid at the lower and stable oxidation potential. Moreover, it exhibited strong stability after prolonged usage. The oxidation peak potential at the N-DNW electrode remained unchanged even after exposure to the solution, followed by washing, drying, and storage in laboratory air for 20 days, with minimization of surface contamination. Therefore, the N-DNW unmodified electrode shows promise for the detection of NADH and is attractive for use in a dehydrogenase based biosensor and other analytical applications.