Radical prostatectomy is a common treatment for localized prostate cancer. More than 30% of men who undergo surgery will subsequently develop recurrence, particularly in patients with adverse features where the risk may be even higher. Recurrence typically manifests as a rise in serum-level of prostate-specific antigen (PSA), referred to as biochemical recurrence.Post-operative radiotherapy is a potentially curative option for many patients, as shown in multiple prior randomized studies. A standard course of post-operative radiation requires 6 to 6 and half weeks of treatment, 5 days a week; however, new high-precision radiation techniques with image guidance, termed stereotactic body radiotherapy (SBRT), can deliver an equivalent or higher dose of treatment in 5 visits.Our group, amongst others, have demonstratedin previous studies, funded by RFD, that the new 5-treatment technique was safe, convenient and effective in patients with intact prostates. Currently, limited data exists on this approach after prostatectomy. This study will be one of the first to assess the side effect profile and efficacy of SBRTin patients with localized prostate cancer who are considered candidates for post-prostatectomy radiation.