The Inner-City Asthma Study is a randomized, controlled trial of two interventions for urban children with moderate to severe asthma. Boston is one of seven sites around the country involved in the NIH-funded project. An anticipated 144 children, four to twelve years old, will be recruited at each site. The study will evaluate two interventions that are hypothesized to improve asthma control: an intensive program to reduce allergens in the home that may contribute to the child's asthma; and a system of monitoring the child's asthma and providing feed back of the child's primary care physician with the goal of enhancing asthma therapy. Children will be randomly assigned to receive the interventions for 12 months. All subjects will be followed for 24 months.