The outcome of teaching the core of knowledge to clinicians and the impact of the POPUMET regulations was assessed using an anonymous questionnaire. 82 of 120 (76%) of non-radiologists responded, of these 37% had attended a radiation protection course. Course attendance improved knowledge of the existence of the POPUMET regulations (p < 0.0001) and the ALARA principle. Course attendance made no difference to knowledge of the relative radiation dose of various radiological procedures. An underestimation of radiation dose was made by all responders (p < 0.001). The majority of responders were not aware that patients have no annual dose limit and the majority did not know the relative radiosensitivity of different organs. We have shown that despite the POPUMET regulations the majority of clinicians have not received adequate radiation protection teaching and that even if a course has been attended overall knowledge is still poor. We propose that formal compulsory teaching at undergraduate level may correct this in the future.