The transfer of tetramethyl-p-phenyle-diamine (TPD) across the water/nitrobenzene interface was investigated by cyclic voltammetry. The transfer mechanism of TPD is derived from its electrochemical behavior. The effect of pH on the transfer behavior was discussed in detail. The standard interfacial potential difference ΔοWψO, and standard Gibbs energies, ΔοWψO of TPD were calculated. The transfer process was also supported by differential pulse and convolution voltammetry, and visible spectroscopic studies. The linear relationship between peak current ip and concentration of TPD demonstrates the potential for analysis of TPD.