Olopatadine is a tricyclic compound with antihistaminic, mast cell-stabilizing, and anti-inflammatory properties. In the United States olopatadine is approved as a b.i.d. ophthalmic solution, Patanol (Alcon Laboratories, Inc., Fort Worth, TX) to treat all signs and symptoms of allergic conjunctivitis and as a q.d. formulation, Pataday (Alcon Laboratories, Inc.), to treat itching associated with allergic conjunctivitis. A nasal spray, Patanase (Alcon Laboratories, Inc.), was approved in 2008 for treatment of the symptoms of seasonal allergic rhinitis. The available data on olopatadine was assessed with regard to future uses through a comprehensive literature review and a Roundtable Discussion held at the 2009 meeting of the American Academy of Allergy Asthma and Immunology. The unique mechanisms of action of olopatadine still under study include mast cell stabilization, potent H(1)-anthistaminic activity, and anti-inflammatory effects. Data support consideration of nasal olopatadine for as-needed use for episodic symptoms of allergic rhinitis, for treatment of nonallergic rhinitis, and for use in combination with topical steroids for patients with moderate-to-severe allergy symptoms.