Abstract The dielectric constant and the equivalent conductivity of solutions of hexadecyl and octadecylamine hydrochloride have been measured at the frequencies of 2 Mc./ sec. and 30 Mc./sec. The dielectric constant of the solutions shows a considerable increase beyond the concentration for micelle formation. The dielectric constant and the equivalent conductivity of the solutions of these amine salts in aqueous ethanol of various concentrations have been measured. The rise of the dielectric constant is diminished with increasing concentration of ethanol. The effect of solubilization of benzene on the dielectric constant of the solutions has been investigated. The relative increase in the dielectric constant is reduced with increasing amount of solubilized benzene. From these experimental results, it is concluded that the rise of the dielectric constant of the aqueous solutions is mainly due to Debye-Falkenhagen’s effect.