The cause of obstructive sleep apnea and snoring is multifactorial. The hypopharynx and velopharyngeal areas are believed to be the main regions of airway collapse in patients with sleep-disordered breathing. The nasal airway is increasingly being recognized as a contributing factor. Nasal airflow resistance accounts for up to 60% of the total respiratory resistance with the nasal valve representing the flow-limiting segment. Patients with nasal obstruction are more likely to be habitual snorers and have a higher prevalence of hypopnea or obstructive sleep apnea (OSA). There is no linear relationship between the severity of nasal obstruction and the severity of snoring or OSA, however. The external nasal dilator increases the nasal valve area and therefore may have a role in the treatment of patients with snoring. The outcome of pharyngeal surgery for patients with OSA is dependent on the presence of nasal obstruction. Patients with severe nasal obstruction are less likely to benefit from uvulopalatopharyngoplasty compared with patients with patent nasal airways. Nasal surgery performed for the relief of nasal obstruction was also reported to improve coexisting snoring even without simultaneous pharyngeal or palatal surgery. Therefore, nasal surgery should be considered in the treatment of snoring or OSA, especially for patients with nasal airway obstruction.