This paper deals with the investigation of the effect of ultrasonic energy on the dissolution of pyrite ores in acidic and Fe-2(SO4)(3) solution. In the effect of ultrasound on the dissolution at various temperatures was experimentally investigated, while keeping the particle size and the solution concentration constant. The same experimental runs, without using ultrasound, were performed and the results were compared. According to these results, it was observed that ultrasound increased the conversion fraction by approximately 30% compared with the experimental results without ultrasound.