Nijmegen Questionnaire allows to assess and identify respiratory symptoms and dysfunction, and to assess unexplained respiratory symptoms and symptoms of hyperventilation syndrome. Determining whether Turkish version of Nijmegen Questionnaire is a valid and reliable tool in asthmatic individuals will guide researchers for further studies on identifying appropriate treatment approaches for the patient and developing different treatment strategies. Hyperventilation syndrome is a recognized form of respiratory dysfunction associated with biochemical factors. Hyperventilation syndrome is defined as breathing above the body's metabolic requirements. This results in decreased carbon dioxide pressure in the arterial blood, respiratory alkalosis, and increased symptoms. Complex symptoms such as shortness of breath, chest tightness, paresthesia, anxiety, and dizziness may occur. There is no laboratory test which is the gold standard in the diagnosis of hyperventilation syndrome. If it is concluded that the Turkish version of the Nijmegen Questionnaire is a valid and reliable test in individuals with asthma, a new tool will be introduced to the literature for the evaluation of pulmonary dysfunction in asthmatic individuals.