Rhinosinusitis is a significant health problem, causing significant morbidity and resulting in considerable financial cost. Some patients suffer persistent or recurrent symptoms despite receiving optimal medical and surgical treatment. Rhinosinusitis can be acute or chronic, acute often due to viral or bacterial infections and chronic which is classified into chronic with nasal polyposids or chronic rhinosinusitis without nasal polyposis. The disease affects the quality of life significantly and presents a significant burden on health costs globally. The anatomical linkage of the nose with the paranasal sinuses facilitates a common pathology in both organs. Chronic rhinosinusitis (CRS) has heterogeneous origins, including viruses, bacteria, fungal infections, anatomical abnormalities, polyposis, and aspirin sensitivity. Other conditions such as human immunodeficiency virus acquired immunodeficiency and cystic fibrosis may also be predisposing factors. Nasal polyposis is often associated with increased numbers of Th2 lymphocytes, fibroblasts, goblet cells, mast cells, and eosinophils, with upregulation of IL-13 and the release of specific IgE to staphylococcal enterotoxins. There is recent evidence that antibiotic treatment may not be as effective as higher doses of intranasal steroids in acute uncomplicated rhinosinusitis, especially in those with allergic disease. The broad inflammatory basis of the pathology of CRS also reveals a cellular infiltrate theoretically suppressed by intranasal corticosteroids. This has been confirmed in recent clinical studies of CRS with or without polyps. A treatment approach based on such studies reported in the European Position Paper on Rhinosinusitis guidelines and a guideline summary are presented. The current review represents the proceedings of a session (3 talks) by the authors at the first Middle East-Asia Allergy, Asthma, Immunology Congress in 2009.