Data came from interviews of a nationally representative sample consisting of 25,500 persons. Results revealed that an estimated 13.6 million people used an illicit drug at least once during the 30 days prior to the interview; the slight decline from 1997 was not statistically significant. A total of 9.9 percent of youths age 12-17 reported current use of illicit drugs in 1998, a statistically significant decrease from the estimate of 11.4 percent in 1997. An estimated 4.1 million people, including 1.1 million youths ages 12-17, met diagnostic criteria for drug dependence in 1997 and 1998. One hundred thirteen million people age 12 and older reported current use of alcohol. About 33 million of these people engaged in binge drinking; 12 million were heavy drinkers. A total of 10.5 million current drinkers were ages 12-20 in 1998. An estimated 60 million people reported current cigarette use. Youths aged 12-17 who currently smoked cigarettes were 11.4 times more likely to use illicit drugs and 16 times more likely to drink heavily than nonsmoking use. Fifty-six percent of youths age 12-17 reported that marijuana was easy to obtain in 1998. Three thousand youths began smoking cigarettes each day in 1997. The prevalence of illicit drug use among persons 12 years and older was 7.2 percent in California, 7.4 percent in Arizona, and 6.1 percent in the rest of the United States. Figures, appended methodological information and tables, and 67 references