This is a pilot study of the effect of montelukast in subjects with asthma who are 65 years old and older. Montelukast is a leukotriene receptor antagonist U.S. F.D.A. approved for the treatment of asthma in subjects who are 12 month old and older. This study is being done because there has been no placebo controlled study of montelukast focused on this group of patients. Elderly asthmatics have been mostly ignored in asthma studies. They are more likely to be underdiagnosed, undertreated, and hospitalized for asthma when compared to younger asthmatics. The pathophysiology of asthma in the elderly is typically different than in younger patients. This is a double-blind, placebo-controlled, crossover study. Investigators plan to enroll thirty subjects who have been diagnosed with asthma for at least one year, are non smoker, and did not smoke for more than 10 pack/year of tobacco products in their lifetime. After a run-in period of one week, the study subjects will take montelukast 10 mg orally for 8 weeks first and then placebo for 8 weeks, or vice versa. Primary objectives of this study are to evaluate the effect of montelukast on asthma symptoms assessed by daily symptom scores, the Asthma Control Test and the number of puffs of albuterol, and spirometric values (FEV1). Secondary objectives include studying whether montelukast affects peripheral blood eosinophils counts and serum IgE levels.

Inclusion Criteria:

• Asthma diagnosed for at least one year;
• Able to swallow small capsules.

Exclusion Criteria:

• Tobacco smoking for more than 10/pack years;
• Previous adverse reaction to montelukast or other leukotriene inhibitor;
• History of hypereosinophilic disorder other than atopic disease;
• Treatment with montelukast within 4 weeks from randomization;
• Asthma exacerbation or treatment with prednisone/other systemic steroid within 4 weeks from randomization.