There is controversy about the effectiveness of monitoring of asthma treatment based on the fraction of exhaled nitric oxide (FeNO). We performed a systematic review of the literature on the effectiveness of FeNO-guided asthma treatment in children. Up to the end of March 2009, four randomised controlled trials were published, but the results of the trials could not be pooled. Their methodological quality was moderate to high. There was no significant effect of FeNO-guided asthma treatment on the number of symptom-free days, asthma exacerbations, hospital admissions, pulmonary function history (except one trial) and quality of life. There was a moderate effect on prednisone use. Children receiving FeNO-guided treatment used prednisone less often than children whose treatment was based on symptoms. However, children receiving FeNO-guided treatment used higher doses of inhaled corticosteroids. At this moment, FeNO-guided asthma treatment cannot be recommended in general practice and paediatric care.