The literature on the costs of treating alcohol-impaired motor vehicle crash victims is largely based on inpatient data. Less is known about the more frequent emergency department (ED) evaluations for those who are discharged home. Our objective is to measure the difference in charges and length of stay between alcohol-impaired and nonimpaired drivers in this population. This was a retrospective study of charts and billing data for all drivers in motor vehicle crashes, aged 21 to 65 years, treated at an urban Level I trauma center in 2005 and discharged home from the ED. Patients were divided into alcohol-positive and -negative groups according to alcohol level, documentation of recent alcohol use, or clinical intoxication. Itemized charges were tabulated and compared across groups. Of 1,618 eligible patients, median charges were higher for alcohol-positive patients by $4,538 (95% confidence interval [CI] $2,755 to $5,665). Imaging was 69% of the charge differential because of a higher frequency of imaging (91% versus 70%) and more expensive studies (median difference $2,464; 95% CI $1,507 to $3,400) for alcohol-positive patients. Median length of stay was higher for alcohol-positive patients by 3.3 hours (95% CI 2.7 to 4.1 hours). When stratified by trauma-protocoled triage destination, median charges were higher for alcohol-positive versus -negative patients in non-critical care beds by $2,229 (95% CI $1,039 to $2,693). For patients triaged to critical care beds, the difference in charges was only $132 (95% CI -$1,677 to $1,233). The presence of alcohol substantially increased charges and length of stay for ED evaluations of injured drivers discharged home, especially for patients who were triaged to non-critical care beds. The magnitudes are striking for this minimally injured population and represent an underreported burden of alcohol-impaired driving.