The report provides data about the prevalence of the use of illicit drugs, alcohol, and cigarettes for the U.S. household population and for four age groups: 12 to 17, 18 to 25, 26 to 34, and 35 and older. It also examines trends in the prevalence of the use of illicit drugs, alcohol, and cigarettes for the U.S. household population between 1972 and 1990, as well as the demographic correlates of the use of illicit drugs, alcohol, and cigarettes among members of the U.S. household population. Also, it provides information on the patterns of use, problems that result from use, and perceptions of the harmfulness of using illicit drugs, alcohol, and cigarettes among members of the U.S. household population. In addition, the report provides an overview of the prevalence of the use of illicit drugs, alcohol, and tobacco among members of the household population in the Washington, D.C., Metropolitan Statistical Area. The principal demographic correlates of drug use examined are age, gender, race/ethnicity, population density, geographic region of residence, education attainment among those aged 18 and older, and current employment status among those aged 18 and older. The drugs for which information is provided are marijuana, cocaine, inhalants, hallucinogens, heroin, nonmedical use of psychotherapeutic drugs, alcohol, cigarettes, and smokeless tobacco. Findings show that in 1990, 37 percent of the household population reported having ever used an illicit drug, 13.3 percent reported having used in the past year, and 6.4 percent reported having used in the past months. The most commonly used illicit drug was marijuana, with 33.1 percent of the household population reporting use in their lifetime, 10.2 percent reporting use in the past year, and 5.1 percent reporting use in the past month. Appended supplementary information and 90 tables