Prostate specific antigen (PSA) failure occurs in 20% to 50% of patients who undergo radical prostatectomy. There is no consensus on how PSA failure should be managed. Recently, salvage radiotherapy is reported to be an effective treatment for PSA failure, and 20%-70% of cases are recurrence-free. The aim of salvage radiotherapy is a cure and this is quite different from other options, for example, endocrine therapy. Salvage radiotherapy is likely to become more important as a treatment for PSA failure after radical prostatectomy.