The prevalence of drug use in the male arrestee population is determined by the Arrestee Drug Abuse Monitoring Program II (ADAM II). The major drugs monitored are marijuana, crack and powder cocaine, heroin and other opiates, and methamphetamine. Four sections follow an executive summary: ADAM II overview; the ADAM II sample; drug use and drug market activity among arrestees; and summary and conclusions. The most commonly detected drug was marijuana followed by cocaine metabolites.