The ac. conductivity σ and dielectric properties [dielectric constant έ, dielectric loss ε˝ and loss tangent (tan δ)] were measured as a function of frequency from 102 to 106 Hz for the mixed ferrites Mg1- x Zn x Fe2 O4 (where × = 0 to 0.6). It was observed that the ac conductivity σ is independent of frequency for f < 104 Hz, but for f > 104 Hz the conductivity σ increases strongly with frequency. It was found that the maximum values of σ lies in the range of frequency corresponding to the peaks of tan δ. The relaxation time (τ) was calculated for the samples of x = 0, 0.2, 0.3 and 0.4 and it was found to be about 2 x 10-6 sec. The electrical conduction mechanism was explained in terms of the electron hopping model. The frequency exponential factor (s) was estimated and it was found to vary between 0.49 and 0.77.