CEWG was established by the National Institute on Drug Abuse and has functioned as an early warning system, predicting the drug abuse patterns and trends. The 21-member CEWG team correctly predicted the epidemics of crack cocaine and the recent "club drug" phenomenon. Information reported at the CEWG meetings are disseminated to drug abuse prevention and treatment agencies, public health officials, researchers, and policymakers in an effort to provide accurate data concerning drug abuse patterns and trends throughout the United States. CEWG members draw on a number of data sources for their work, include emergency room drug mentions data; drug-related mortality data; substance abuse treatment admissions data; arrestee drug-testing data; forensic drug laboratory data; and drug seizure, trafficking, price, and purity data. At the 54th semiannual meeting, CEWG members presented research findings concerning drug abuse patterns, trends, and emerging issues. Following a brief introduction focusing on CEWG data sources, participant papers are presented by area. Cities under investigation in these reports include Atlanta, Baltimore, 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, DC. The 2003 meeting also included a panel discussion on the emerging problem of methadone-associated mortality; presentations on drug abuse in Missouri; presentations on the status of the National Institute of Justice's (NIJ's) Arrestee Drug Abuse Monitoring (ADAM) program and the Drug Enforcement Administration's (DEA's) National Forensic Laboratory Information System (NFLIS); an update by staff on the status of the Drug Abuse Warning Network (DAWN); and presentations on status and data produced by the surveillance systems in Mexico and Canada. A listing of CEWG meeting participants is provided. Exhibits