Treatment of asthma in the emergency department (ED) or hospital accounts for a significant portion of total treatment costs; however, little is known about the specific resources consumed. The purpose of this study was to estimate the type and amount of resources consumed for an asthma event requiring ED visit and/or hospitalization. Between October 1, 1996 and September 30, 1997, occurrences of asthma as a primary diagnosis were identified at 27 hospitals' emergency departments within Premier's Perspective Comparative Database. Patients visiting the ED could either be treated and released or admitted to the hospital. A total of 3,223 patients (age >/= 18 yr) were identified, with 1,074 (33.3%) requiring hospitalization. For the 2,149 patients who visited the ED only, the average visit cost was $234.48. For hospitalized patients, the average length of stay was 3.8 d, and the cost was $3,102.53. Nursing care was the source of the majority of hospital costs for asthma (43.6%), respiratory therapy (13.6%), and medications (10.4%). For adult asthma patients requiring hospitalization, the total cost is high and resources consumed are unavoidable. Thus, a continuum of care aimed at appropriate asthma management, especially in the elderly, could result in substantial cost savings over those aimed at reducing inpatient utilization of care.