Classification of fungal rhinosinusitis is important for the accurate prediction of prognosis and direct therapy. The most important distinction is between invasive and noninvasive fungal rhinosinusitis. Within the invasive division are acute invasive and chronic invasive (granulomatous and nongranulomatous forms) rhinosinusitis. Within the noninvasive division are saprophytic colonization, fungus balls, and allergic fungal rhinosinusitis. This article briefly outlines the definition and management of each of these manifestations.