Numerous studies have reported an association between nasal obstruction and obstructive sleep apnea syndrome (OSAS), but the precise nature of this relationship remains to be clarified. This paper aimed to summarize data and theories on the role of the nose in the pathophysiology of sleep apnea as well as to discuss the benefits of surgical and medical nasal treatments. A number of pathophysiological mechanisms can potentially explain the role of nasal pathology in OSAS. These include the Starling resistor model, the unstable oral airway, the nasal ventilatory reflex, and the role of nitric oxide (NO). Pharmacological treatment presents some beneficial effects on the frequency of respiratory events and sleep architecture. Nonetheless, objective data assessing snoring and daytime sleepiness are still necessary. Nasal surgery can improve the quality of life and snoring in a select group of patients with mild OSAS and septal deviation but is not an effective treatment for OSA as such. Despite the conflicting results in the literature, it is important that patients who are not perfectly adapted to CPAP are evaluated in detail, in order to identify whether there are obstructive factors that could be surgically corrected.