Introduction. Adenoid hypertrophy leading to upper airway blockage is the most common cause of sleep apnoea syndrome in children. Moreover, the following disturbances can occur: normal speech resonance impairment, middle ear ventilation difficulties, and the development of an abnormal oral breathing pattern. Abnormal craniofacial growth and occlusal abnormalities can be observed as well. Objectives.The aim of the study was to confirm the relationship between respiratory disorders with the impaired upper airway patency resulting from reduced nasopharyngeal space. Moreover, an attempt was made to validate a new medical device, a NasoOroSpirometer, for diagnosing respiratory disorders resulting from adenoid hypertrophy. Design and Setting The NasoOroSpirometer is made up of three anemometric sensors (two nasal and one additional oral sensor) and is used to measure the airflow through the upper airways (UA). A measurement of the flow of air simultaneously through both nasal orifices was carried out in 105 children aged 4-8 years. The values obtained included the number of inhalations per minute, the inspiratory time and the inhalation volume. Results and discussion. The study demonstrated that children with adenoid hypertrophy had a statistically significantly lower number of inhalations through the nose than children from the control group. The current results demonstrated no statistically significant difference between the volume and the number of inhalations in both a combined analysis and in one analysis conducted separately for each nasal passage. The demonstrated statistically significant difference is most probably due to the oral compensation for the inefficient nasal respiratory pattern. A NasoOroSpirometric examination can be a screening tool in the assessment of UA patency disorders and an indicator for the eligibility for instrumental or imaging examinations.