Little is known about the extent of exercise prescription within cancer care. This cross-sectional survey aims to identify Irish oncology nurses and physiotherapists' current knowledge and practice in prescribing exercise for cancer care and barriers to such prescription. An online survey was distributed to the Chartered Physiotherapists in Oncology and Palliative Care (n = 35) and the Irish Association for Nurses in Oncology (n = 170). The response rate was 74% (26/35) for physiotherapists and 34% (58/170) for oncology nurses. Three quarters of physiotherapists recommended/prescribed exercise with 81% or more of cancer patients in the past 6 months, with the exercises prescribed largely in line with current guidelines. Patients' family/friends advising rest was the most commonly reported exercise barrier by physiotherapists [89% (17/19)], with a lack of exercise guidelines for cancer patients being most problematic for oncology nurses [93% (50/54)]. Only 33% (18/54) of oncology nurses felt they had sufficient knowledge regarding exercise in cancer care. In conclusion, exercise prescription by physiotherapists largely corresponds with current guidelines. A minority of nurses felt they had sufficient knowledge of exercise for this population. Further formal postgraduate educational opportunities are needed for oncology nurses and physiotherapists in this area.