The nasal septum was surgically removed from 22 horses with upper airway obstruction caused by thickening and/or deviation of the septum. The most common presenting complaints were a low‐pitched, snoring, respiratory noise and respiratory difficulty during exercise, which usually occurs in young horses. Abnormalities of the septum were most commonly congenital defects or caused by trauma or inflammation secondary to severe respiratory infection.Diagnosis was made based on history, clinical signs, and results of physical examination. Radiography and endoscopy were useful adjuncts in some horses.Under general anesthesia, the septum was removed by scalpel and osteotome (19 horses) or by obstetrical wire and osteotome (1 horse). In two horses, the rostral one third of the septum was removed by scalpel alone.In three horses, the alar folds and floor of the nasal diverticula were removed in an attempt to relieve airway obstruction caused by flattening of the bridge of the nose following removal of the nasal septum.Follow‐up was obtained on 18 horses: persistent noise during exercise continued in 90%; however, 50% returned to usefuln