Thin films from pure dichloroethane (DCE) and from solutions of benzyldimethylhexadecyl ammonium tetraphenyl berate in DCE, formed between air and 0.1 M aqueous KCl were studied using the microinterference method for determining the thickness of the films and the dynamic method for obtaining the isotherm of the disjoining pressure. The value of the Hamaker constant in the van der Waals component of the disjoining pressure for these systems was estimated. The influence of the electric polarization applied between the aqueous phase and the DCE phase on the time of life of the films and on the electric current between the phases was investigated as well. The electric conductivity of the solutions was measured. The interfacial tension at the DCE/water interface was determined by the drop-weight method. Thin films from pure DCE, formed on the surface of 0.05% saponin solutions in 0.1 M aqueous KCl were studied by the microinterference method and the obtained results for the lifetimes of the films and their critical thickness were discussed.