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Blood eosinophil count is established as a biomarker to identify those COPD patients with an eosinophilic phenotype. These patients are most likely to respond to inhaled corticosteroids. Recent evidence supports a role for anti-eosinophilic biologic therapy in reducing exacerabations in this subgroup. FeNO is commonly used to identify Type 2 airway inflammation in asthma, but its role in COPD is uncertain. We examined the utility of measuring FeNO in a severe COPD clinic.A retrospective review of the records of patients attending a tertiary COPD clinic was performed, and those with FeNO recorded were identified. The prevalence of FeNO≥25ppb, and FeNO ≥50ppb was established. The relationship between FeNO measurement and baseline demographic and clinical data was examined.Data from 82 patients was included. The mean (sd) age was 56 (9) years; 55% were female. All patients had post-bronchodilator airflow obstruction with mean FEV1 54 (22.5)%, and high symptom burden, mean CAT 20.3 (8.2). The majority were ex-smokers (71%). Mean FeNO measured 19.6 (14.2) ppb, and peak blood eosinophil count 0.28 (0.22) cells/mm 3, in the previous year. An ICS was prescribed in 79%. Only 7% had a diagnosis of co-existent asthma.An elevated FeNO≥50ppb was present in 5% of patients; 29% had a FeNO≥25ppb. There was an inverse relationship between FeNO and age. FeNO levels were higher in ex-smokers; FeNO >25 in 38% compared to 8% in current smokers (p < 0.01). One quarter of those prescribed ICS recorded FeNO≥25ppb. There was no significant relationship between FeNO and lung function, previous diagnosis of asthma, CAT score, or peak eosinophil count.Almost one-third of patients referred to a tertiary severe COPD clinic have FeNO ≥25ppb suggesting FeNO is a useful adjunct in the assessment of COPD patients, regardless of smoking status, and ICS prescription. As is seen in asthma, FeNO and eosinophil count are independent biomarkers in this cohort. Integrating FeNO assessment into COPD care may enhance therapeutic precision but requires consideration of clinical context to maximise its effectiveness. More studies are needed to examine whether FeNO response to ICS differs in COPD patients as compared to those with asthma.