In 169 children with a runny nose the difference between the group with rhinitis and those diagnosed as having sinusitis was indistinct. History and examination, and the results of radiology, ultrasound, the appearance of the sinus washings, the number of leucocytes in the washings, and the presence of pathogenic bacteria in the culture of the secretion from the nose and sinuses had little correlation with each other or with the clinical picture. In our view there is no marked difference between rhinitis and simple sinusitis, that is, mucosal inflammation of the maxillary sinus. This difference is also of no therapeutic relevance, and both diseases may be regarded as part of an upper airway infection. It is important to distinguish between sinusitis with and without empyema, because empyema must be treated differently. The latter disease produces distinct symptoms in the acute stage resembling ethmoiditis in children or maxillary and frontal sinusitis in adults. This type of sinusitis did not occur in our patients. Further investigation in children with a runny nose is indicated only in those with typical symptoms of an empyema.