Rhinosinusitis is one of the most common disorders encountered by primary care physicians and ear nose and throat (ENT) specialists. It is therefore surprising that no consensus exists on the definition of the disease nor the classification of its different clinical forms. This review aims to discuss the definitions and classification of infectious rhinosinusitis, together with a summary of current views on its etiology and management, resulting from the deliberations of an international group of clinicians with a special interest in this area.