Chronic rhinosinusitis and asthma are not simply localized disease processes, but part of a systemic inflammatory disease affecting the respiratory tract. There is a correlation between severity of asthma and the clinical and imaging features of rhinosinusitis. It is very important to understand that in patients with chronic sinus disease, both upper and lower airways need to be evaluated and treated and that in patients with moderate or severe asthma, the sinus area should always be investigated, regardless of the presence or not of nasal symptoms. Nasal endoscopy may be considered a feasible and correct approach in asthmatic children to investigate rhinosinusal or adenoid infections, even if they do not present with any clinical sign. Thus, it becomes more and more important to perform a simple, easy and safe nasal endoscopy, in order to have a better chance to treat asthmatic children correctly by identifying a subclinical or an occult rhinosinusal infection.