Asthma is the most prevalent chronic childhood condition and is the most frequent cause of hospitalization among children. There are about 6.7 million children in the U.S. who currently have asthma, and nearly two of every three of these children had at least one attack in the past 12 months. Evidence suggests that exposure to cockroach allergen might be the most important risk factor for asthma in inner-city households. An environmental intervention targeting only cockroach allergen could potentially provide cost savings in a public health program over high cost multi-component interventions, if it could be shown to reduce asthma morbidity.