Lung cancer is the major cause of death from neoplastic disease in the world, and even with politically-motivated smoking cessation campaigns throughout Europe, the disease remains the major cause of death. The development of molecular epidemiological population-based research into early lung cancer detection, such as the Liverpool Lung Project (LLP), may provide a way forward. This is the first major molecular epidemiological study of detection of early lung cancer. The use of molecular epidemiological risk assessments prior to clinical diagnosis and markers of preclinical carcinogenesis in patients with a high risk of developing lung cancer will reduce the incidence of clinically-detectable lung cancer, given the appropriate intervention strategies. The aims are as follows: 1) to prepare a molecular genetic and epidemiological risk assessment model based on environmental exposures and genetic predisposition; 2) to develop an archive of specimens relating to at-risk individuals and those with lung cancer; 3) to redefine lung cancer based on molecular pathology using the fields of expression profiling, genetic instability and molecular cytogenetics; 4) to identify and assess novel markers of precarcinogenesis in high-risk populations; and 5) to facilitate the development of new treatment strategies (e.g. chemoprevention programmes and targeted drug therapies). The LLP has two components: 1) a case-controlled study of newly-diagnosed cases of lung cancer that will provide a baseline, risk assessment; and 2) a prospective cohort study to be carried out over a 10-yr period that will identify markers of preclinical carcinogenesis. In-depth interviews are carried out using structured and semi-structured questionnaires. Sputum, blood and tumour specimens are collected and will be assessed for specific molecular markers (e.g. genetic instability, mutation and expression profiling, and methylation status). Conclusions from The Liverpool Lung Project will be based around molecular-epidemiological and genotyping risk assessment models, as well as redefining the disease, and ultimately contributing to the development of new early lung cancer detection and treatment strategies.