Introduction and aims Assessment of chest radiographs is a fundamental clinical skill, often taught opportunistically. Medical students are taught how to read adult chest radiographs, however, in our experience, there is often a lack of structured training for the interpretation of pediatric chest radiographs. Our aim was to develop and evaluate an online approach for medical students to learn this skill. Materials and methods Ericsson's expertise acquisition theory was used to develop 10 sets of 10 practice radiographs which were graded using the X-ray difficulty score. Medical student volunteers (from Keele University School of Medicine) were recruited in the paediatric rotation of their first clinical year. Pre- and post-training tests of identical difficulty were offered. A semistructured focus group was conducted after the tests, the transcription of which was analyzed using grounded theory. Results Of 117 students in the year, 54 (46%) originally volunteered. The engagement was initially high but fell during the year, particularly during the pre-examination block. The high drop-out rate made the quantitative measurement of effectiveness difficult. The focus group suggested that pressure of other work, exam preparation, technical factors, and inflexibility of the study protocol reduced engagement. Conclusions Although the topic covered was seen as important and relevant to exams, the current system requires development to make it more effective and engaging.