The previously established mechanism of two-phase nitration has been revised by proposing an additional mode of reaction, viz., interfacial nitration. The interfacial mechanism involves adsorption of the nitronium ion at the interface, followed by its reaction with the aromatic substrate present in the interfacial monolayer. The evidence for the proposed mechanism is provided by the results of the experiments, conducted in this work, on nitration of nitrobenzene. Relative magnitudes of the bulk and the interfacial rates during the nitration of nitrobenzene have been determined. The effects of interfacial area, concentrations of sulfuric and nitric acids, and addition of surfactant and inert diluent in the organic phase on the rate of interfacial nitration are studied. On the basis of the proposed mechanism, plausible explanations have been provided to the anomalies in the rates of nitration, observed under the industrially relevant operating conditions.