Mometasone furoate nasal spray (MFNS; Nasonex, Schering-Plough Corporation, Kenilworth, NJ, USA) is an effective and well-tolerated intranasal corticosteroid approved for the prophylactic treatment of seasonal allergic rhinitis, and the treatment of perennial allergic rhinitis. MFNS is a potent molecule with a rapid onset of action and excellent safety and efficacy profiles. Having recently received approval for the treatment of nasal polyposis, data indicate that MFNS may also be effective in rhinosinusitis.