Asthma is the leading cause of chronic disease in childhood, and morbidity and mortality are on the rise, particularly among urban Black and Hispanic children. It is hypothesized that, compared with their white counterparts and children without asthma, 4- to 11-year old Black and Hispanic children with asthma have a greater number of medical, psychosocial, and environmental risk factors and that the severity and complications of asthma are related to the presence and/or interaction of these risk factors. It is further hypothesized that an intervention to reduce the number of risk factors is feasible and that an appropriate intervention will reduce asthma-related morbidity. In the first phase of the study, asthmatic children will be identified through a screening program in practices, clinics, emergency rooms, and schools. Children with mild/moderate and severe asthma will undergo a battery of medical tests and psychosocial surveys to determine asthma history and the presence or absence of selected medical, psychosocial, and environmental risk factors. Nonasthmatic and white children will be evaluated for the same risk factors in order to assess the relationship between the presence of risk factors and the presence and severity of asthma. Parents will also be evaluated for the presence of adult risk factors, such as poor parenting skills and limited understanding of asthma. The asthma histories of a subsample of children with sever asthma will be reconstructed in detail. The second phase of the study will involve a four-armed intervention targeted to reduce morbidity in Black or Hispanic children with severe asthma. The intervention-which will include both parents and children-will be designed primarily to address the psychosocial risk factors identified in Phase I. All subjects will receive usual care. Controls will receive no intervention; children/parents in the second arm will receive office-model case-management; in the third arm, children/parents will receive an educational and behavioral component plus office-model case-management. (At present, it seems likely that the Open Airways and STEP programs will be used for educational and behavioral intervention, respectively). In the fourth arm, children/parents will receive the educational and behavioral component plus more intensive case management that will include home visits and assistance with some problems of daily living. The results from the four arms of the intervention will be compared to ascertain the level at which intervention becomes effective. The goal is to reduce the numbers of days missed from school, hospitalizations, and emergency room visits. An effective intervention to reduce morbidity would be a significant health benefit to asthmatic Black and Hispanic children, and it would also provide substantial economic relief both to families of asthmatic children and to the overburdened urban health-care system.