For the vast majority of asthmatic children, treatment with inhaled glucocorticoids is safe and effective. Mild impairment of adrenal function of doubtful clinical significance is known to occur in some children inhaling ≥400μg/day budesonide and beclomethasone or ≥200μg fluticasone. Recent reports of life-threatening adrenal failure in asthmatic children inhaling glucocorticoids, some of whom were prescribed licensed doses, have prompted the recommendation that the use of high-dose inhaled glucocorticoids, particularly fluticasone, should be avoided. However, the importance of correctly diagnosing asthma, of using the minimum dose of inhaled glucocorticoid required for symptom control and of regular growth-velocity assessment cannot be over-emphasised. Appropriate asthma management including the early introduction of steroid-sparing agents such as a long-acting β-agonist or leukotriene antagonist may reduce the morbidity associated with inhaled glucocorticoid use but some children, for reasons as yet unknown, may exhibit increased sensitivity to the systemic effects of inhaled glucocorticoid treatment. Possible explanations for this, with reference to the pharmacology and molecular mechanisms of glucocorticoid action, are accompanied in this review by a summary of the recent case reports and discussion of assessment of adrenal function.