Phase III multicenter study was conducted in the USA under the FDA approved protocol, to establish the safety and efficacy of High Intensity Focused Ultrasound (HIFU) in the treatment of Benign Prostatic Hyperplasia (BPH) using the Sonablate? system. A total of sixty eight patients have been treated to date in the Phase III study. Transrectal probes capable of real-time ultrasound imaging of the prostate and well as delivering the HIFU energy to the selected region in the prostate gland were used. Probes with different focal lengths were used to treat different size of prostate glands. The patients were treated in one treatment session and were followed up to a period of one year following the treatment. The subjects underwent physical exam, Digital Rectal Examination (DRE), cystoscopy, Transrectal Ultrasound (TRUS), blood work, urine exam and were given standard questionnaires before treatment and during the follow up period. Under this protocol HIFU was found to be safe and effective in reducing the BPH related symptoms and improving the peak urinary flow rate with preservation of sexual function and no permanent side effects.