OBJECTIVES: To explore the prevalence of substance use among emergency medicine (EM) residents and compare to a prior study conducted in 1992. METHODS: A voluntary, anonymous survey was distributed in February 2006 to EM residents nationally in the context of the national in-service examination. Data regarding 13 substances, demographics, and perceptions of personal patterns of substance use were collected. RESULTS: A total of 133 of 134 residencies distributed the surveys (99%). The response rate was 56% of the total EM residents who took the in-service examination (2,397/4,281). The reported prevalence of most illicit drug use, including cocaine, heroin, amphetamines, and other opioids, among EM residents are low. Although residents reporting past marijuana use has declined (52.3% in 1992 to 45.0% in 2006; p < 0.001), past-year use (8.8%-11.8%; p < 0.001) and past-month use (2.5%-4.0%; p < 0.001) have increased. Alcohol use appears to be increasing, including an increase in reported daily drinkers from 3.3% to 4.9% (p < 0.001) and an increase in number of residents who indicate that their consumption of alcohol has increased during residency (from 4% to 12.6%; p < 0.001). CONCLUSIONS: Self-reported use of most street drugs remains uncommon among EM residents. Marijuana and alcohol use, however, do appear to be increasing. Educators should be aware of these trends, and this may allow them to target resources for impaired and at-risk residents.