The total sample was composed of 309 school-children and their parents. A total of 154 families were represented in the group with children defined as non-drug users, and 155 families were represented in the group with children defined as drug users. The children's drug use was determined through a self-report questionnaire that included frequency measures for the use of legal and illegal drugs, family relationships, parental monitoring, parents' drug use, and perception of the accessibility of legal and illegal drugs. Parents were also administered a similar questionnaire. The study found that parents of children who used drugs tended to significantly underestimate their children's use of drugs. Also, they overestimated the control they believed they exercised over their children. Parents with children who used drugs were apparently more familiar with drug use than the parents of children who did not use drugs. Parents' lack of knowledge about the extent of their children's drug use, together with lack of awareness of risk factors in family dynamics, suggest that parents of drug users may not believe they need to seek resources for help. Drug prevention programs must find ways to address these two forms of denial in parental perceptions before parents will be motivated to participate in prevention and family intervention programs. 3 tables and 25 references