This paper deals with the investigation of the effect of ultrasonic pretreatment on the mechanical flotation of zinc from lead-zinc-copper ore. After the chosen flotation parameters such as KAX dosage, frother amount, flotation time, stirring rate and amount of Na2SiO3, were optimized by flotation experiments without ultrasonic pretreatment, flotation experiments with ultrasonic pretreatment were carried out under these optimized conditions. The results obtained by both methods were compared. A zinc concentrate containing 8.52% Zn was obtained from feed containing 1.60%Zn with 24.64% recovery using mechanical flotation method without ultrasonic pretreatment. On the other hand, a concentrate containing 18.73%Zn was obtained with 33.18% recovery using flotation with ultrasonic pretreatment. It has been concluded that, ultrasonic pretreatment improved the grade and recoveries in zinc flotation due to the energy released by cavitation bubbles generated in the ultrasonic cleaning bath. XRD analysis were also supported the positive effect of ultrasonic pretreatment on flotation.