Background: Although transferring drugs to a third party, even in a personal capacity, is illegal in Japan, many drug transactions are carried out via internet auction sites. Pharmacy consumers might not be aware of the illegality of transferring drugs to others due to various factors. To clarify pharmacy consumers’ awareness of this issue and its covariates, we carried out a questionnaire survey.Methods: A self-completed questionnaire, consisting of yes/no and multiple-choice questions, was used. The adult patients who visited Keio University Pharmacy were asked to fill out the questionnaire.Results and Discussion: One hundred and fifty-one response sheets were effectively collected from 173 responders. The subjects’awareness of the illegality of transferring drugs was significantly affected by the formulation (oral vs. patches) and pharmacological category of the drug, as well as the source of the drug (prescribed vs. over the counter). Patient education about the illegality of personally transferring drugs, especially patches, might be required to avoid illegal drug transfers, including via the internet.