The nitration of naphthalene (NapH) at a Pt electrode in aqueous NaNO2 solutions both in the absence and presence of a non-ionic surfactant, Brij(R)35 (polyoxyethylene (23) dodecanol), has been studied. The electrochemical behaviour of the reactants NapH and NaNO2 and a mixture of the two was investigated by cyclic voltammetry (CV) to determine the optimal electrolysis conditions. The peak current of NapH decreases with increasing NaNO2 concentration, indicating that the oxidation product of the NO2- ion interacts with the NapH radical cation (NapH(.+)). Controlled potential electrolysis (CPE) was carried out and the products were analysed by HPLC. The main products detected in the micellar medium were 1-nitronaphthalene, 2-nitronaphthalene, 1,2-naphthoquinone, and 1,4-naphthoquinone. In the absence of Brij 35, the naphthoquinones were produced but no nitration products were obtained. In both cases, unknown products are inferred by mass balance, which are believed to be derived from the oxidation of 1,1'-binaphthyl (BinapH) formed by NapH(.+) coupling in both micellar and aqueous media. A mechanism of nitration by the attack of NO2 to NapH(.+) is proposed. The higher selectivity for formation of 2-nitronaphthalene in comparison to non-aqueous homogeneous media is attributed to the effect of the micellar microenvironment.