The aim of this study was to explore the social representations used by the parents of adolescent drug users to explain the onset of drug use. Differences in explanations between the parents of male and female adolescents were also explored. Sixty parents who accompanied their children to four rehabilitation centers in 2004 completed two semi-structured questionnaires. In addition, indepth interviews were applied to a subsample. The explanation of the drug use was carried out through two social representations: the neglectful family and the son or daughter as an inexperienced teen. The parents-son model was well structured; however, the parents-daughter was unstructured, which suggests a higher resonance in the familial group.