The survey sought information from all freestanding facilities that treat only alcohol or other drug abuse and from specialized drug treatment units within hospitals and other multipurpose health care institutions. The broad characteristics of facilities and persons served displayed either stability or gradual change between 1980 and 1995, except for growth in the number of persons served. In addition, States differed significantly in the number of persons treated as a proportion of the general population, in the drug abuse problems being treated, and in the mix of outpatient versus 24-hour care. More than 1 million persons were in specialty drug treatment on October 2, 1995. Forty-six percent of the persons abused both alcohol and drugs, 31 percent abused only alcohol, and 23 percent abused only drugs. The proportion of women in treatment increased from 25 percent to 30 percent of the persons in treatment between 1980 and 1995. Sixty-two percent of the persons in treatment were white, 22 percent were black, and 13 percent were Hispanic. Eighty-six percent of the individuals were in outpatient care. Overall, facilities used 67 percent of their perceived outpatient capacity and 68 percent of their 24-hour capacity. Facilities with only private funding shifted more rapidly than others from 24-hour to outpatient services from 1980 to 1995. Figures; tables; 16 references; and appended glossary, list of other sources of national treatment data, methodological information, and instrument