The CEWG is a network composed of researchers from major metropolitan areas of the United States and selected foreign countries. It meets semiannually to discuss the current status of illicit nonmedical drug use. The primary mission of the CEWG is to provide ongoing community surveillance of drug abuse, principally through the collection and analysis of epidemiologic and ethnographic research data. The CEWG provides current descriptive and analytical information on the nature and patterns of drug abuse, emerging trends, and characteristics of vulnerable populations. The 20 cities assessed in these proceedings are Atlanta, Boston, Chicago, Denver, Detroit, Honolulu, Los Angeles, Miami, Minneapolis/St. Paul, Newark, New Orleans, New York City, Philadelphia, Phoenix, St. Louis, San Diego, San Francisco, Seattle, Texas, and Washington, D.C. To assess drug abuse patterns and trends, city-specific and State-specific data were obtained from a variety of health and other drug-abuse indicator sources. In addition to the assessments of the seven foreign countries already mentioned, regional presentations were made on substance abuse epidemiology in the Caribbean region and Central America and on epidemiologic issues related to the Commission of European Communities and the Pan American Health Organization. Drug categories encompassed in the assessments were cocaine; heroin; other opiates; marijuana; stimulants; antidepressants, barbiturates, and sedatives/hypnotics; and hallucinogens. Extensive tabular and graphic data are provided.