The bulk impedance parameters of various fluoride glasses series containing a large extent in NaF rate have been determined from an analysis of ac conductivity data measured in a wide temperature range. The charge carriers concentration in each glass studied has been evaluated using the Almond-West formalism and shown to be temperature independent. Transport properties in these materials are due to a hopping mechanism of the fraction of F- ions mobile at long range (3-5%). The variation of different conductivity parameters as a function of the NaF content has been determined. When the NaF rate increases, a conductivity decrease is observed, due mainly to a decrease of the charge carriers mobility.