Breathlessness (or dyspnoea) is a common symptom experienced by cancer patients. It may be iatrogenic and is often caused or aggravated by co-morbidity. Recent studies have elucidated the neural and chemical controls of breathing which may be involved in the production of dyspnoea. A rational approach involves making a diagnosis of aetiology and treating reversible causes wherever possible. The main approaches for palliation of dyspnoea include anti-cancer treatments; drugs; oxygen and airflow; non-medical approaches. Further research is needed to clarify the best pharmacological regimens and the place of more invasive interventions.