The most efficient method to deliver drugs to the lungs in children is the inhaled way. Its success depends on the characteristics of the aerosol, on those of the patient, and mainly on the inhalatory system. Before the age of 8 years, the most efficient system is the pressurised metered dose inhaler used together with a spacer device. Above this age, the use either of the pressurised metered dose inhaler, with a spacer device or a breath-actuated inhaler, or of a dry powder inhaler is discussed. Nebulisation is rarely indicated, except in cystic fibrosis. Demonstration with repeated medical instructions allows adequate inhalation technique. Inhaled treatments are efficient when used in diseases requiring this type of treatment, when several inhalers with different inhalatory techniques are not prescribed together, and when delivery is once or twice daily. At last, inhaled way is a new approach for different drugs with an extra-respiratory activity.