We report the electrical conductivity and the conductivity relaxation of the mixed alkali fluoride glasses in the system 50ZrF(4)-20BaF(2)-5YF(3)-5AlF(3)-(20-x)LiF-xNaF (0less than or equal toxless than or equal to20) in the frequency range from 10 Hz to 2 MHz and the temperature range from 300 to 473 K. We have analyzed the electrical data in the framework of the conductivity as well as the modulus formalism. We have observed the mixed mobile ion effect in the conductivity and the conductivity relaxation in these mixed alkali fluoride glasses. The characteristic relaxation frequency obtained from the conductivity formalism and the conductivity relaxation time obtained from the modulus formalism exhibit minimum at different relative concentration.