In 1998 the ADAM program expanded from 23 to 35 urban sites across the United States. Across the 35 urban sites currently participating in ADAM in 1998, adult male respondents tested positive for recent (within 72 hours) opiate use at rates ranging from a high of 18.4 percent in Philadelphia to a low of 1.3 percent in Atlanta. For the 32 sites that collected data on female arrestees during 1998, the proportion of arrestees who tested positive for opiates ranged from 27.0 percent in Chicago to no positive tests in Laredo. Generally, a higher proportion of female arrestees than male arrestees tested positive for opiates at both new and veteran sites. Male arrestees showed opiate- positive rates in excess of female arrestees by at least 5 percentage points in only three sites. Analysis of opiate- positive arrestees who participated in the ADAM program between 1990 and 1998 suggests that little has changed over the past 9 years for this group of arrestees. Many opiate users also use other drugs; from 1990 to 1998, almost 70 percent of arrestees who tested positive for opiates also tested positive for cocaine, and nearly 25 percent tested positive for marijuana use. Although generally opiate-using arrestees do not use methamphetamine, sites with high rates of methamphetamine also found users combining opiates and methamphetamine. In the coming years, it will be important to monitor whether additional sites begin to see a shift among opiate-positive arrestees to younger age cohorts, as well as the extent to which opiate-using arrestees continue to use other drugs. 6 tables