Previous studies have shown an increased frequency and duration of apnoeic episodes during sleep when the nose is occluded. The aim of this study was to ascertain whether oxygen desaturation occurs with nasal occlusion by postoperative packing. Continuous digital pulse oximetry was carried out before and after submucous resection of the nasal septum in 17 otherwise healthy patients. Post-operative nasal packing produced a statistically significant change in oxygen saturation during sleep. The change was, however, of such small magnitude that it is unlikely to be clinically significant.