TThis is a randomized, crossover, placebo controlled trial of 30 patients, 7-17 years old with confirmed EIB. Patients will be randomized to montelukast treatment for at least 3 days or pretreatment with albuterol before an exercise challenge. Villiran and colleagues have shown that the protective effect of montelukast in treating EIB is apparent at day 3 of treatment and comparable to treatment for 4 and 8 weeks.