Preferring to remain anonymous, drug abusers are generally identified as they seek treatment or when they are arrested. However, many persons abuse drugs and never receive any therapeutic intervention. Because the drug-abusing community is poorly defined and services to it are typically provided by a potpourri of resources, containment of AIDS among this group becomes a serious public health issue. It is probable that drug abusers are at substantially higher risk for AIDS than are homosexuals. When sexual preference is disregarded, IV drug abusers represent more than one-quarter of all AIDS cases. Data from the Treatment Outcome Prospective Study (TOPS), a large-scale longitudinal study supported by the National Institute on Drug Abuse, are representative of the subpopulation of drug users who enter treatment. TOPS is based on 3 annual cohorts (1979, 1980, 1981) of clients admitted to more than 40 drug abuse treatment programs throughout the country. A stratified random sample of all clients was interviewed at 90 days, 1 year, and 2 years posttreatment to determine the relative effectiveness of their treatment experiences. Findings reveal that proportionately, blacks constituted the majority of IV drug users; heroin and narcotics were used by 70 percent of subjects; and the majority of heroin users reported administering drugs intravenously. Additional, most drug IV users in a small New York City survey knew and were concerned about AIDS, drug abuse treatment staff are concerned about the dangers of handling specimens from a population that might be at great risk of developing AIDS, educational programs on AIDS are needed for treatment providers. 4 tables and 23 references.