The survey conducted telephone interviews with 10,227 adults regarding their use of tobacco, alcohol, and 9 other classes of drugs, as well as problems they had experienced related to their substance use. Because sampling was done within regional strata and included some oversampling of hard-to-find demographic groups, post-stratification weights were used to ensure that the final estimates would be representative of the State population in terms of gender, age, racial/ethnic composition, and regional distribution. Almost 90 percent of adults reported having used alcohol at some time during their lives, and almost 70 percent had used tobacco products; 4 percent had tried inhalants. In the past year, almost 66 percent of adult Texans had drunk an alcoholic beverage, and 5.7 percent were current heavy drinkers (defined as having had five or more drinks on five or more occasions during the past month). Approximately 29 percent had used tobacco, and less than 1 percent had used inhalants during the past year. The most prevalent illicit substance reported being used was marijuana (37 percent). Approximately 12 percent had ever used powder cocaine, and similar percentages had ever used "uppers" (primarily diet pills and "speed") and psychedelics (hallucinogens such as LSD, Ecstasy, and psilocybin mushrooms). About 7 percent had used "downers" (primarily Valium and Xanax); 4 percent had used opiates other than heroin (mainly codeine, vicodin, and hydrocodone); 2 percent had used crack cocaine; and slightly more than 1 percent had used heroin. During the past year, 9.4 percent of adults had used an illicit substance, with the most prevalent drug being marijuana (7 percent). In 2000, 33.6 percent of adults had used neither alcohol nor any other drug (excluding tobacco) during the past year. Approximately 57.1 percent had used alcohol exclusively, and 8.7 percent had used both alcohol and other drugs. Most respondents who had used illicit drugs had used only one kind. Men were substantially more likely than women to have used alcohol, tobacco, or most other drugs in the past year. Adults under the age of 25 were the most likely to have used any substance, and those over 35 years old were the least likely. The relationship between race/ethnicity and substance use varied. Anglos and Hispanics were more likely than African-Americans to have smoked in the past year. Anglos were the most likely and African-Americans the least likely to have drunk alcohol, although there was no significant difference in heavy drinking. There was no racial/ethnic difference in the rate of overall past-year illicit drug use; however, there were some differences in the prevalence of the use of specific drugs. An analysis of drug-related problems focuses on dependence or abuse, residential instability, trends in substance problems, mental health disorders, gambling, and multiple problems. Findings on treatment experience and current needs are discussed as well as are regional differences. 14 tables, 13 figures, and appended supplementary data