The guidelines for the management of asthma currently emphasise the concept of monitoring that reflects the activity of the disease over a period of several weeks. This principle is valid whatever the severity of the asthma. The monitoring tools are essentially clinical and functional. The clinical parameters (daytime and/or nocturnal symptoms, discomfort on exercise, beta-2 agonist usage) should be evaluated systematically at each consultation just as at the onset of exacerbations. A number of questionnaires have been developed (ATAQ, ACT...). At the functional level every asthmatic child should have the benefit of a respiratory function assessment, the frequency of which depends on the therapeutic management programme. Among the non-invasive measurements of airway inflammation the measurement of expired nitric oxide (NO) is the best established. The measurement of expired NO could improve some paraclinical parameters that are not monitored routinely.