The Liverpool Lung Project (LLP) is being conducted within a defined geographic area of Merseyside, based on contiguous districts with a high incidence of lung cancer. As well as increasing the scientific understanding of the interactions between the different risk factors for lung cancer, the LLP aims to develop a model which predicts lung cancer risk from an extensive record of epidemiological risk factors, molecular/genetic risk factors and from changes in molecular biomarkers, which maybe used in early detection programmes. The LLP has two components: Firstly, a case-control study of 800 newly diagnosed cases of lung cancer matched 2:1 for age (+/-2 years) and gender will facilitate the development of the molecular genetic and epidemiological model to assess an individual's risk of developing lung cancer. Secondly, a prospective cohort study will recruit 7,500 individuals to identify markers of pre-clinical carcinogenesis in a high-risk population and validate and strengthen the molecular genetic and epidemiological risk assessment model. Structured questionnaires collect detailed information on lifestyle factors (active and passive smoking, medical history, family cancer history, occupation, residence and diet) over the whole life course. Collection of biological specimens includes blood, sputum, bronchial lavage, oral scrapes and tumour. Cohort study subjects will be followed up over a 10-year period. In addition, serial biological samples (blood and induced sputum) will be collected from a high-risk subgroup of the cohort. The LLP protocol provides detailed information on the study design and analysis strategy, together with the informed consent documentation and the LLP lifestyle questionnaire. Conclusions from the LLP programme will be based around epidemiological and genotyping risk assessment models enabling us to identify high-risk populations, and will ultimately contribute to, and facilitate the development of effective prevention, early detection and chemoprevention strategies.