Recurrent disease following primary radiotherapy for localized prostate cancer is a common problem, occurring in up to 46% of patients. For these patients, therapeutic options include salvage prostatectomy, salvage cryotherapy, salvage high-intensity focused ultrasound (HIFU), hormonal therapy or observation. This review will focus on the emerging evidence for salvage HIFU. There are no randomized or prospective studies in this area. Efficacy results of 17-57% have been reported from retrospective case series, with reported toxicity including rectal fistula in 0-16%, and incontinence in 10-50%. The ideal patient, while yet to be clearly defined, should have preradiotherapy low or intermediate risk disease. Salvage HIFU appears most appropriate for those patients with histologically proven local recurrence only, with a life expectancy of at least 5 years and with some medical comorbidities rendering them not ideal for salvage prostatectomy.