Purpose: chemotherapy/radiotherapy-induced nausea and vomiting (CINV/RINV) can affect half of oncology patients, significantly impacting daily life. Nausea without vomiting has only recently been thought of as a condition in its own right. As such, the incidence of nausea is often underestimated. This survey investigated the incidence and impact of CINV/RINV in patients compared with estimations of physicians/oncology nurses to determine if there is a perceptual gap between healthcare professionals and patients. Methods: an online research survey of physicians, oncology nurses and patients was conducted across five European countries. Participants had to have experience prescribing/recommending or have received anti-emetic medication for CINV/RINV treatment. Questionnaires assessed the incidence and impact of CINV/RINV, anti-emetic usage and compliance, and attribute importance of anti-emetic medication. Results: a total of 947 (375 physicians, 186 oncology nurses and 386 patients) participated in this survey. The incidence of nausea was greater than vomiting: 60 % of patients reported nausea alone, whereas 18 % reported vomiting. Physicians and oncology nurses overestimated the incidence of CINV/RINV but underestimated its impact on patients' daily lives. Only 38 % of patients reported full compliance with physicians'/oncology nurses' guidelines when self-administering anti-emetic medication. Leading factors for poor compliance included reluctance to add to a pill burden and fear that swallowing itself would induce nausea/vomiting. Conclusions: there is a perceptual gap between healthcare professionals and patients in terms of the incidence and impact of CINV/RINV. This may lead to sub-optimal prescription of anti-emetics and therefore management of CINV/RINV. Minimising the pill burden and eliminating the requirement to swallow medication could improve poor patient compliance with anti-emetic regimens.