In the United States, driving while impaired is illegal. Nonetheless, an estimated 10,511 alcohol-impaired driving deaths occurred in 2018.* The contribution of marijuana and other illicit drugs to these and other impaired driving deaths remains unknown. Data from the Substance Abuse and Mental Health Services Administration's National Survey on Drug Use and Health (NSDUH) indicated that in the United States during 2014, 12.4% of all persons aged 16-25 years reported driving under the influence of alcohol, and 3.2% reported driving under the influence of marijuana (1). The impairing effects of alcohol are well established, but less is known about the effects of illicit substances or other psychoactive drugs (e.g., marijuana, cocaine, methamphetamines, and opioids, including heroin). This report provides the most recent national estimates of self-reported driving under the influence of marijuana and illicit drugs among persons aged ≥16 years, using 2018 public-use data from NSDUH. Prevalences of driving under the influence of marijuana and illicit drugs other than marijuana were assessed for persons aged ≥16 years by age group, sex, and race/ethnicity. During 2018, 12 million (4.7%) U.S. residents reported driving under the influence of marijuana in the past 12 months; 2.3 million (0.9%) reported driving under the influence of illicit drugs other than marijuana. Driving under the influence was more prevalent among males and among persons aged 16-34 years. Effective measures that deter driving under the influence of drugs are limited (2). Development, evaluation, and further implementation of strategies to prevent alcohol-impaired,† drug-impaired, and polysubstance-impaired driving, coupled with standardized testing of impaired drivers and drivers involved in fatal crashes, could advance understanding of drug- and polysubstance-impaired driving and support prevention efforts.