Respiratory pathologies, including asthma, chronic obstructive pulmonary disease, lung cancer and fibrosis, impose significant health care burdens on populations throughout the world. The goal of this meeting is to bring together basic and clinical scientists studying a range of topics including: mechanisms underlying the embryonic development and maturation of the normal lung, endogenous stem cells and their role in repair and regeneration, the genetics of human lung diseases, and the cells-of-origin and progression of cancer and fibrosis. The format will be designed to promote critical discussion and debate and collaboration among participants who do not traditionally go to the same scientific meetings. The emphasis will be to stimulate new ways of thinking about old problems and new ideas about potential therapies. A common theme will be the question of how the different cell types in the lung – the epithelium, vasculature, mesenchyme and immune cells – interact during development and how these mechanisms may be disrupted or re-activated in association with disease initiation and progression. Based on participant feedback from the 2011 Keystone Symposia meeting on Lung Development and Repair there will be more workshop style sessions in which specific technical issues will be critically discussed, and junior clinician scientists and trainees can learn about different models of lung development, lung injury and repair, and lung stem cells. Other sessions will address emerging issues in lung biology, including new cellular therapies, the effect of environmental factors, and the identification of genes and pathways associated with rare lung diseases that have the potential to throw light on broader issues of lung biology.