OBJECTIVES: Evidence supporting the use of adjuvant radiation therapy (ART) versus salvage RT (SRT) following prostatectomy in prostate cancer patients with high-risk disease is inconclusive.  We sought to compare and contrast US and Italian Radiation Oncologists (RO) beliefs and practices on the use of ART and SRT in the treatment of prostate cancer following prostatectomy. METHODS: A 34-question, web-based survey on post-prostatectomy prostate cancer ART and SRT treatment attitudes was distributed to US and Italian RO.  Survey invitations were e-mailed to a sample of 926 US RO selected from the American Society for Radiation Oncology membership directory, and to all 716 Italian RO listed in the Italian Association of Radiation Oncology roster. Bivariate, chi-square analyses to compare US and Italian RO responses on ART and SRT beliefs and practices were performed. RESULTS: The US survey had 218 respondents (24% response rate), while the Italian survey had 154 respondents (21.5% response rate). Both US and Italian RO routinely recommend ART, but more US than Italian RO would initiate ART based solely on adverse pathological features in the prostatectomy specimen (79.4% vs. 68.4%, p<0.05).  70% US RO believed ART improves survival outcomes compared to 35.5% Italian RO (p<0.05).  A striking difference in ART use, timing, dosage, and technique was found between Italian and US RO. More US RO would initiate salvage therapy based on any detectable PSA compared to Italian physicians (36.8% vs. 11.3%, p<0.05); Italian RO, in contrast, were more likely than US OR to initiate SRT upon higher PSA levels.  CONCLUSIONS: Much variation is seen between US and Italian RO in regards to use of ART and SRT in prostate cancer patients after prostatectomy.  More clinical studies should be undertaken in order to provide better evidence on ART versus SRT use in clinical practice.