Allergic diseases are common in all age groups and locations around the world. In the United States, allergic diseases affect 20 to 40 million people annually, including 10% to 30% of adults and close to 40% of children. An estimated 15 million people in the United States have been diagnosed as having asthma, with this number on the rise. Concomitant asthma affects 67% of patients who have allergic rhinitis. As a result of the increase in ventilation during exercise, athletes in particular experience significant symptoms of allergy triggered by exposure to aeroallergens. The allergic response causes nasal and conjunctival congestion, tearing, breathing difficulties, pruritus, fatigue, and mood changes, which affect athletic performance. Systemic symptoms of anaphylaxis from allergy, although rare, can be life threatening. Several decades ago it was inconceivable that an athlete who had asthma could perform competitively, let alone win Olympic gold medals. Today, with proper diagnosis, education, and optimal therapeutic management, the allergic athlete can achieve great strides in all sports endeavors. To avoid seasonal allergic flares and maximize performance, the physician providing care for an athlete who has seasonal allergies must be aware of the climatic patterns of aeroallergen expression, and adjust exercise and pharmacologic regimens accordingly. This article summarizes the effects of allergic disease on exercise and highlights the challenges that seasonal allergy place on athletic performance. Doping considerations grant additional complexity to this issue and underscore the need for a competent, skillful, informed, and ethical approach to treating seasonal allergy in the competitive athlete.