The electrical conductivity of ammonium nitrate + formamide mixtures was measured as a function of temperature for the ammonium nitrate concentration range (0 to 17) mol center dot kg(-1) The report describes the application and validity of Casteel-Amis equation to fitting the experimental data as a function of salt content in the electrolyte in the temperature range (303.15 to 353.15) K. Also, the densities of the mixtures were determined pycnometrically at different temperatures and ammonium nitrate concentrations for all of the investigated melts.