Though Americans make 1.8 million asthma-related outpatient visits to the emergency department (ED) annually, little is known about the episodic charges for asthma care in the ED. We therefore sought to assess the bills patients could face for acute asthma incidents by examining hospital charges for asthma-related outpatient ED visits. We performed a nationwide, cross-sectional study of 2.9 million weighted asthma-related outpatient ED visits from 2006–2008 using data from the Medical Expenditure Panel Survey. We found that the average charge for an outpatient ED visit was $1,502 (95% CI $1,493–$1,511). The charges did not vary significantly by insurance group but did increase significantly with age. Our results indicate that the financial burden of ED care for asthma may take a severe toll on low-income populations who have limited ability to pay, especially patients who must pay undiscounted charges, including the uninsured and those on high-deductible health plans.