This study is designed to assess the effectiveness of mometasone furoate nasal spray (MFNS) once daily compared with placebo in subjects with seasonal allergic rhinitis (SAR) in reducing the total symptom score.

Inclusion Criteria:

• Must be 12 years of age or older, of either sex and of any race.
• Must have at least a 2-year documented history of SAR which exacerbates during the study season.
• Must have a positive skin-prick test response to an appropriate seasonal allergen at Screening (Visit 1). IgE-mediated hypersensitivity to an appropriate seasonal allergen (ie, prevailing trees and/or grasses) must be documented by a positive response to the skin prick test with wheal diameter at least 3 mm larger than diluent control after 20 minutes.
• Must be clinically symptomatic at the Screening Visit.
• Must be clinically symptomatic at the Baseline Visit.
• Must be in general good health as confirmed by routine clinical and laboratory testing and ECG results. Clinical laboratory test (CBC, blood chemistries, and urinalysis) must be within normal limits or clinically acceptable to the investigator and the sponsor.
• Must be free of any clinically significant disease, other than SAR, that would interfere with the study evaluations.
• A subject and/or a parent/guardian must be willing to give written informed consent and must be able to adhere to dosing and visit schedules and meet study requirements.
• A female subject of childbearing potential must have a negative serum pregnancy test (HCG) at Screening. Nonsterile and premenopausal female subjects must be using a medically acceptable method of birth control, ie, double barrier method, oral contraceptive, hormonal implant, or depot injectable prior to Screening and during the study.

Exclusion Criteria:

• A history of anaphylaxis and/or other severe local reaction(s) to skin testing.
• A subject with asthma who require chronic use of inhaled or systemic corticosteroids.
• Current or history of frequent, clinically significant sinusitis or chronic purulent postnasal drip.
• A subject with rhinitis medicamentosa.
• A history of allergies to more than two classes of medications or who are allergic to or cannot tolerate nasal sprays.
• A subject who have had an upper respiratory tract or sinus infection that required antibiotic therapy without at least a 14-day washout prior to the Screening Visit, or who have had a viral upper respiratory infection within 7 days before the Screening Visit.
• A subject who has nasal structural abnormalities, including large nasal polyps and marked septal deviations, which significantly interfere with nasal air flow.
• A subject who, in the opinion of the investigator, is dependent on nasal, oral, or ocular decongestants, nasal topical antihistamines, or nasal steroids.
• Use of any drug in an investigational protocol in the 30 days before the Screening Visit.
• A subject on immunotherapy (desensitization therapy), unless the subject is on a regular maintenance schedule prior to the Screening Visit and will stay on this schedule for the remainder of the study. A subject may not receive desensitization treatment within 24 hours before any visit.
• Pregnant or nursing females.
• Family member of the investigation study staff.
• Current evidence of clinically significant hematopoietic, cardiovascular, hepatic, renal, neurologic, psychiatric, autoimmune disease, or other disease that precludes the subject's participation in the study. Particular attention should be given to exclude subjects with conditions that would currently interfere with the absorption, distribution, metabolism, or excretion of the study drug or interfere with the subject's ability to complete or reliably complete the diaries.
• Significant medical condition(s) that, in the judgment of the investigator, might interfere with the study or require treatment.
• A subject whose ability to provide informed consent is compromised.
• A subject with a history of noncompliance with medications or treatment

protocols.