INTRODUCTION: This study aimed to assess understanding of the potential risks associated with medical imaging among caregivers and adolescent patients in a paediatric emergency department (PED) in Singapore. METHODS: A prospective convenience sample survey was performed involving adolescents and caregivers presenting to our PED from December 2015 to May 2016. The questionnaire examined demographic data, knowledge of imaging procedures and radiation risks, and expectations regarding information provided about medical radiation. RESULTS: A total of 349 questionnaires were returned (caregivers 82.5%, adolescents 17.5%). A mean of 6.2 ± 2.4 (out of 11) questions were correctly answered. Those who had tertiary education fared better than those who did not (36.4% vs. 17.2% scoring above the mean, p = 0.001). Age, gender, history of previous imaging and imaging performed during the visit did not affect the score. Two-thirds of the participants did not associate medical radiation with any negative lifetime risk of cancers or know that different scans entailed differing amounts of radiation. Most were unaware that the radiation dose in medical imaging is adjusted to a child's size. Among patients who underwent imaging, 90.1% received explanations on the need for scans, and 26.5% were informed of the risks involved. Almost all participants wished to be informed of imaging indications and risks. More preferred to learn this from physicians (75.6%) or technicians (51.6%) rather than through educational pamphlets (34.4%) or Internet resources (22.9%). CONCLUSION Awareness regarding medical radiation needs to be improved in our patient population. A mismatch exists between caregiver expectations and the actual procedure of disclosure of the risk associated with radiation.