This article describes the development of a novel model for quality assurance of pediatric asthma using administrative data and clinical guidelines. Children for whom drugs for asthma were dispensed during 1998 were recruited from the drug-dispensing registry of the largest health maintenance organization in the southern region of Israel. The Israeli clinical guidelines were translated into a list of six markers for inadequate treatment. This list was used for a computerized search in the drug registry, and cases with markers were noted as cases in which inappropriate treatment was provided. The model was validated by proving that there was an association between inappropriate treatment (markers) and bad outcomes (emergency room visits, hospitalizations, and healthcare utilization). This model creates an interface between administrative and clinical information and provides an easy-to-use tool for quality assurance.