The current paradigm is that untreated lung cancer is invariably and rapidly fatal, therefore the medical community normally dismisses the idea that a patient could live with such a disease for years without any therapy.Yet evidence from lung cancer screening research and from recent clinical series suggests that, although rarely recognised in routine practice, slow-growing lung cancers do exist and are more common than previously thought.Here, current evidence is reviewed and clinical cases are illustrated to show that slow-growing lung cancer is a real clinical entity, and the reasons why management protocols developed in the screening setting may also be useful in clinical practice are discussed. Features suggesting that a lung cancer may be slow-growing are described and appraised, areas of uncertainty are examined, modern management options for earlystage disease are evaluated and the influence that all this knowledge might have on our clinical decisionmaking is weighed. Further research directed at developing appropriate guidelines for these peculiar but increasingly common patients is warranted. @ERSpublications The increasingly common incidence of slow-growing lung cancer and its influence on clinical decision-making is discussed