In order to derive guidelines for general practitioners on the value of chest radiography we prospectively reviewed all chest radiographs over a 10 month period. Radiographic chest examinations (frontal with or without a lateral view) were performed on 2017 patients in the radiology department or at the chest clinic. Patient details were noted, referring practice and waiting times monitored. The adequacy of the referral letter was assessed, and specific predetermined clinical findings were correlated with the radiographic findings. Results were divided into three groups (normal, abnormal with a clinically unrelated or chronic abnormality, and abnormal with a clinically related abnormality). Of these patients, 1245 (62%) had normal examinations and 460 (23%) had clinically related abnormalities. Abnormalities were rare in the 10-29 year age group, and when reassurance was sought for patients with symptoms of non-specific chest pain or general ill health. Patients presenting with haemoptysis or with symptoms of lower respiratory infection, or of chronic airways disease often had an abnormal radiograph. A clinical diagnosis was indicated or implied in 1664 (82%) and confirmed in 876 (53%). The most frequent reason for referral was for reassurance (618 patients). Guidelines based on age and symptoms should rationalize the use of chest radiography by general practitioners.