INTRODUCTION: Level 1 evidence demonstrates the benefit of postoperative radiotherapy (PORT) for pT3 disease and positive margins. The role of androgen deprivation therapy (ADT) after PORT remains to be defined from results of ongoing randomized trials. This study was undertaken to determine the factors influencing the current use of ADT after PORT amongst Canadian radiation oncologists. METHODS: An institutional survey was emailed to the Genito-urinary Radiation Oncologists Group of Canada (GUROC), designed to assess the likelihood of prescribing ADT in early and delayed PORT scenarios with variations in disease prognosticators. Analysis used descriptive statistics. RESULTS: Majority (94%) do not routinely advocate ADT with PORT. With early PORT and undetectable prostate-specific antigen (PSA), respondents (n = 53) indicated that Gleason Score 8-10 (89%), pT3b disease (80%) and high risk D??Amico category (76%) were important considerations. With early PORT and a detectible PSA, important considerations were PSA doubling time (90%), high risk disease (85%), pT3b category (82%) and time to relapse (TTR) of < 3 months (90%). Similar patterns were observed in the context of delayed PORT with importance given to TTR and PSA velocity. Category pT3b was consistently perceived as a poor prognosticator. The majority of respondents prescribe ADT for > 6months (72%) or > 24 month (48%). CONCLUSIONS: Wide variation was identified among respondents in the importance given to pathological, clinical and biochemical parameters and in considering therapy duration when prescribing ADT with PORT. This demonstrates a need for consensus guidelines and lends support to currently accruing phase III trials designed to answer these questions.