A comparison of the characteristics of the nearly 4,000 male and female arrestees interviewed thus far shows them to be similar to arrestee characteristics in general. Slightly more than half of all arrestees tested positive for an illegal drug, ranking St. Louis near the middle among the cities participating in the DUF program. Cocaine emerged as the drug of choice; 45 percent of all arrestees tested positive for cocaine. Marijuana, opiates (including heroin), and PCP accounted for the remainder of drug use among arrestees. Male and female drug use levels generally were similar. Black arrestees had higher levels of drug use for most categories of drugs tested. Drug use tended to be higher among arrestees in their 20s than those younger or older. A subcategory of arrestees engaged in a large number of behaviors which place them at risk for HIV, namely, large numbers of sex partners and needle sharing. Policy recommendations include treatment and education concerning drug abuse. 8 figures and 13 tables