The molar equivalent electrical conductivity of aqueous ethanol solutions containing ammonium chloride or ammonium nitrate was measured under high pressure, up to 400 MPa, at 298 K. The concentration range of the ammonium salts in solution was broad because their solubility is relatively high compared with that of other salts. A common result was that the molar equivalent electrical conductivity decreased as a function of solute concentration. Additionally, the molar equivalent electrical conductivity decreased considerably when the ethanol content was increased and decreased slightly as the pressure was increased. The molar equivalent electrical conductivity was treated as a function of the square root of electrolyte molality, in accordance with the Debye-Huckel-Onsager equation, but could not be represented by one function because of dependence on ethanol concentration and on pressure. Therefore, use of the electrolyte-nonrandom two-liquid (NRTL) model is proposed for extending the Debye-Huckel-Onsager equation to these two electrolyte solution systems.