DUF information is based on the objective results of anonymous urine testing of samples of arrestees in 22 cities in all parts of the country, and augmented by information from voluntary interviews. The information is analyzed to help cities and policymakers monitor drug use trends and probe what works and what doesn't in drug prevention, education, and enforcement. The results for 1988 indicate that the percentage of males testing positive for any drug at time of arrest ranged from 54 percent to 83 percent. The range for female arrestees was from 44 percent to 81 percent. The relationship of age to drug use differed little from city to city. Drug use was prevalent in male and female arrestees of all races. Multiple drug use was found in all age categories and ethnic groups. Male arrestees were more likely to test positive for marijuana than were their female counterparts, however, in some cities, more females than males tested positive for cocaine. The urine test results for opiates, while low, are reported because of the well-established link between heroin use and crime. 26 tables.