Chronic rhinosinusitis encompasses a group of disorders characterized by inflammation of the mucosa of the nose and paranasal sinuses of at least 12 weeks' duration. In addition to nasal obstruction and discharge, chronic sinusitis is a common cause of olfactory dysfunction. Smell loss can result in problems including safety concerns, hygiene matters, appetite disorders, and changes in emotional and sexual behavior. Although smell loss related to sinonasal disease is probably the most treatable form of olfactory dysfunction and treatment can improve olfactory sensation in the setting of sinusitis, most studies show that the effects are usually transient and incomplete.