There are a number of ways in which understanding the genetic basis of either disease pathogenesis or treatment response might be of value in the management of respiratory diseases. Although some single gene defect respiratory diseases such as cystic fibrosis exist, the majority of common respiratory diseases are caused by the interaction of multiple genes and environmental factors. Newer approaches including the use of genome wide association studies will help define the underlying genetic factors. Understanding the genetic basis for disease will throw new light on the pathophysiology of disease, may help redefine disease subtypes, and may also contribute to therapeutic approaches. The aim of this review is to assess the current state of our knowledge of these areas of research.