The Boston Lung Cancer Study (BLCS) is a cancer epidemiology cohort (CEC) of over 12,000 lung cancer cases enrolled at Massachusetts General Hospital (MGH) and Dana-Farber Cancer Institute (DFCI) since 1992. It has been supported by the National Cancer Institute (NCI). We have collected detailed demographic, smoking, occupational, and dietary information, in addition to pathology, imaging, treatments, oncogenic (somatic driver) mutation status, and biosamples. The BLCS biorepository includes serum, white blood cells, DNA, and ~2,000 tumor and surrounding tissues. This cohort is a member of the NCI-supported International Lung Cancer Consortium (ILCCO) and the Transdisciplinary Research in Cancer of the Lung on Lung Cancer (TRICL), and is one of the few lung CECs contributing data on survival status, with oncogenic mutation data and tissue available. The accumulative follow-up rate for the BLCS cohort has been high, approximately 95%, with nearly complete ascertainment of deaths using the National Death Index and other resources. MGH and DFCI are leaders in systematically genotyping patients for oncogenic mutations.