Finding an abnormality on a plain chest radiograph is usually the first definite evidence of a lung cancer, so this investigation is currently pivotal in the diagnosis of the disease. Although the National Institute for Clinical Excellence (NICE) has produced guidance on when a chest radiograph should be done for putative lung cancer presentations, cancer will usually be only one of a number of possible diagnoses, so this is somewhat artificial. Neither is there any evidence that obtaining a chest radiograph for these features leads to an improved outcome. Another major concern is the poor public awareness of the symptoms for which a chest radiograph is recommended. This article discusses the role of the chest radiograph in the early diagnosis of lung cancer with particular emphasis on the limited value of a single negative result and on the potential implications of interventions to increase the number of chest radiographs done in primary care.