Twelve DUF sites collected quarterly data from male juvenile arrestees and detainees in 1993, using sample sizes ranging from 301 to 452. Results revealed that at most sites, drug use among these youths was limited mainly to marijuana and cocaine. Broad increases occurred between 1992 and 1993 in the extent of marijuana use, but only minor changes occurred in cocaine use. All 12 sites reported an increase the percentage testing positive for marijuana. This percentage ranged from 14 to 51, with a median of 26 percent, compared to a median of 16.5 percent in 1992. With a few exceptions the levels of cocaine use were largely unchanged; the median was 6.5 percent. None of the 12 sites reported percentages of opiate use above 2 percent, a finding that was comparable with the 1992 findings. From 18 to 54 percent of the youths tested positive for at least one drug; the median was 33 percent. The percentage of youths testing positive for multiple drugs ranged from 1 to 14 percent, with a median of 7.5 percent. The youths attending school were less likely than those not attending school to test positive for cocaine. Findings underscored the importance of providing intervention programs for youthful offenders. Figures and tables presenting data from each of the 12 DUF sites