Bronchial carcinoma is the principal cause of cancer death. Unlike cancers of the breast and colon that are already the subject of screening programmes, proof has not yet been provided that screening for bronchial carcinoma is of value in terms of reduction in mortality. Technological improvements and the advent of low dose spiral CT scanning has lead to a recent renewal of interest in this subject. The first preliminary studies seem to indicate that 2/3 of bronchial carcinomas discovered by CT scanning are detected at an early stage. Other data suggest a possible improvement in survival of tumours discovered by screening. Nevertheless it is necessary to demonstrate that screening improves the survival of patients with bronchial carcinoma. The present consensus does not advocate mass screening by CT scanning but that high risk subjects should voluntarily participate in randomised controlled trials which alone will confirm or refute the validity of this approach.