Although the majority of patients with chronic upper airway diseases have controlled symptoms during treatment, many patients have severe chronic upper airway diseases (SCUADs). SCUAD defines those patients whose symptoms are inadequately controlled despite adequate (ie, effective, safe, and acceptable) pharmacologic treatment based on guidelines. These patients have impaired quality of life, social functioning, sleep, and school/work performance. Severe uncontrolled allergic rhinitis, nonallergic rhinitis, chronic rhinosinusitis, aspirin-exacerbated respiratory diseases, or occupational airway diseases are defined as SCUADs. Pediatric SCUADs are still unclear. In developing countries SCUADs exist, but risk factors can differ from those seen in developed countries. Comorbidities are common in patients with SCUADs and might increase their severity. The present document is the position of a group of experts considering that SCUADs should be considered differently from mild chronic upper airway diseases. It reviews the state of the art, highlighting gaps in our knowledge, and proposes several areas for a better understanding, prevention, and management of SCUADs. This document can also serve to optimize the pharmacoeconomic evaluation of SCUADs by means of comparison with mild chronic upper airway diseases.