Stage is with performance status, the most potent prognostic factor in non-small cell lung cancer. In the past decades, much effort has been directed towards the definition, description, development and implementation of staging guidelines. This has undoubtedly resulted in improvements in therapy and insight in the biology of the disease. The new millennium sees us confronted with an increasing epidemic of lung cancer. Hence, the need for further improvements in staging accuracy and cost effectiveness, in order to use the available therapeutic armament at its best and provide the patient with a treatment that is best adjusted to his or her condition. Current controversies and future challenges in staging will be addressed.