Leukotrienes have been shown to cause bronchoconstriction, increased mucus production, and airway inflammation, three critical features in asthma. Antileukotriene drugs were developed to inhibit the effects of these lipid mediators. This class of drugs represents the first new approach to asthma therapy in 25 years. The leukotriene receptor antagonists, montelukast, zafirlukast, and pranlukast, and the 5-lipoxygenase inhibitor, zileuton, are unique in their ability to target specific components of asthmatic inflammation. Although the role of these drugs continues to evolve, the antileukotrienes have demonstrated efficacy against exercise and allergen-induced bronchoconstriction and additive benefit for use in patients with symptomatic, moderate asthma on maintenance-inhaled corticosteroids. Further, they may be considered for primary use in patients with mild, persistent asthma, especially those who are steroid-phobic or who have compliance issues.