Previous research has recorded a high level of illegal drug use among young people in the United Kingdom. However, little is known about illegal drug use among the United Kingdom’s preteen population. This paper reports on research undertaken for the Department of Health’s Drug Misuse Research Initiative, in which 1,202 students aged 10 to 12 years in Glasgow and 1,116 students aged 10 to 12 years in Newcastle were surveyed regarding their activities outside of school, contacts with peers, family structure, family relationships, attitudes toward school, and legal and illegal drug use. Overall, 3.9 percent of the participants had used illegal drugs and another 30 percent reported being exposed to illegal drugs. The level of illegal substance abuse varied greatly between the two cities, with Glasgow participants reporting higher levels of illegal drug use. Cannabis was the most frequently identified drug of use, although a small number of participants reported use of heroin, cocaine, and LSD. The authors estimate that approximately 60 children between the ages of 10 and 12 years will have used heroin in Glasgow and approximately 34 children will have used the drug in Newcastle. Drug use among the preteen sample was associated with frequent smoking and alcohol use, involvement in problematic behaviors, and with having family difficulties that include illegal drug use by another family member. Harm-reduction strategies for children who begin illegal drug use in their preteens is fraught with difficulties that include the identification of this population of drug users and issues of labeling and stigmatization. Tables, references