The Community Asthma Program was designed to increase awareness of asthma among urban residents and to bring more people into available care. Educational sessions with patients indicated that many adults struggle with the complicated demands of managing a chronic disease. At the same time, however, a good deal of the written materials meant to provide information and assistance instead make inappropriate demands on the average adult reader. The project team members developed a glossary of asthma terms to improve communication between patients and providers and to help patients understand the materials commonly used in neighborhood health centers. We report on the development of the glossary and describe formative research activities, initial dissemination efforts, and an interim evaluation. Health literacy, included in the goals and objectives for Healthy People 2010, can be improved when health materials are written in plain language and designed for the existing skills of the average U.S. adult reader.