Since 1980, asthma prevalence, hospitalization, and mortality have been increasing in the United States (1). Because of concern about asthma morbidity in children in King County, Washington (2), Public Health-Seattle and King County (PH-SKC) conducted a study that analyzed trends in local hospitalizations for childhood asthma during 1987-1998. This report summarizes the results of this analysis, which indicate that the youngest children and the poorest communities have the highest rates of asthma hospitalization.