The present investigation dealt with the study of the effect of (1/10LD50) cypermethrin and /or cyhalothrin (two pyrethroids) on the histological structure of albino rat testis. Paraffin and plastic methods were used for this investigation. The histological alterations included atrophy of seminiferous tubules, depletion in the germinal layers and widening of interstitial space. Mixture of both pyrethroids showed synergistic effect with respect to above alterations, while cyhalothrin showed higher effect than cypermethrin. Large sized vacuoles were detected in the interstitial space. The most characteristic feature of the seminiferous tubules of the mixture treated rats was the appearance of multinucleated giant cells.