Objective: To compare the resource utilization and healthcare costs of children with a diagnosis of asthma, children dispensed asthma medications but without a diagnosis of asthma, and control children. Study design: Children 0 to 17 years old were identified from an integrated managed-care data base during calendar year 2001. They were compared on the basis of the presence of a medical claim for asthma (Dx cohort);a prescription for an asthma controller or reliever medication(excluding oral corticosteroids) but without an asthma diagnosis(Rx cohort), and control children. Using medical and pharmacy claims, resource utilization and costs were compared across cohorts. Results: Children in both the Dx and Rx cohorts had significantly greater nonasthma and total all-cause annual healthcare costs compared with control children. The Dx and Rx cohorts had higher rates of nonasthma emergency department visits and hospitalizations. The risk of an oral corticosteroid dispensed was 14-fold and 7-fold greater for the Dx and Rx cohorts, respectively, compared with the control children. These findings were consistent in infant, toddler,school-age, and adolescent groups. Conclusions: Children dispensed asthma medications but lacking an asthma diagnosis have considerable morbidity and incur high healthcare resource utilization. This study suggests that better recognition of pediatric asthma is warranted. Objective: To compare the resource utilization and healthcare costs of children with a diagnosis of asthma, children dispensed asthma medications but without a diagnosis of asthma, and control children. Study design: Children 0 to 17 years old were identified from an integrated managed-care data base during calendar year 2001. They were compared on the basis of the presence of a medical claim for asthma (Dx cohort); a prescription for an asthma controller or reliever (excluding oral corticosteroids) but without an asthma diagnosis (Rx cohort) Using medical and pharmacy claims, resource utilization and costs were compared across cohorts. Results: Children in both the Dx and Rx cohorts had significantly greater nonasthma and total all-cause annual healthcare costs compared with control children. The Dx and Rx cohorts had higher rates of nonasthma emergency department visits and hospitalizations. The risk of an oral corticosteroid dispensed was 14-fold and 7 -fold greater for the Dx and Rx cohorts, respectively, compared with the control children. These findings were consistent in infant, toddler, school-age, and adolescent groups. Conclusions: Children dispensed asthma medications but lacking an asthma diagnosis have considerable morbidity and incur high healthcare resource utilization. This study suggests that better recognition of pediatric asthma is warranted.