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. However, smell loss is often overlooked in the clinical setting of sinusitis, with attention instead focused on the respiratory complaints of nasal obstruction, hypersecretion, and facial pressure and pain. Olfactory dysfunction can result in problems including safety concern, 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, most studies show that improved olfactory sensation in this setting is usually transient and incomplete.