Asthma diagnosis and management are undergoing a paradigm shift, with Fractional exhaled Nitric Oxide (FeNO) increasingly recognised as a valuable biomarker of type 2 airway inflammation. The latest NICE/BTS/SIGN asthma guidelines recommend FeNO as part of the diagnostic and management pathway for asthma. This symposium will explore the rationale for adopting a “FeNO first” approach, the scientific and clinical evidence underpinning these guidelines, and the practical considerations for implementation in everyday practice.