Research and application of genomic medicine in lung disease during the past century has clarified our understanding and focus on specific phenotypes, helping clinicians tailor treatment for individual patients. Cystic fibrosis and lung cancer have been researched extensively; specific genotypes have been instrumental in precision medicine to treat these lung diseases. Asthma and chronic obstructive pulmonary disease are more complex and heterogeneous in their pathogenesis, genotypic profile, and phenotypic expression, making treatment more difficult with increasing disease severity. This article focuses on the evolving state of the science of precision medicine in lung cancer, chronic obstructive pulmonary disease, asthma, and cystic fibrosis. The body of knowledge in lung disease is growing related to pharmacogenomics, clinical guidelines, genome editing, and approaches to genomic health that will guide clinical treatment options, reduce risk, and promote health.