<p>Objective: The proportion of young patients in Japan in whom generic drugs are used is lower than that of other age groups. To promote the use of generic drugs in young patients, we need to change the parents’ attitude toward generic drugs. Therefore, we aimed to contribute to the maintenance and reform of the Japanese social security system by investigating the effects of parent’s sex, patient’s age, and use of the children’s medical expense subsidy system on the selection of generic drugs. Method: We surveyed parents of young patients (<20 years) whose prescriptions were filed at pharmacies from November 25 to December 1, 2019. Results: Of the 712 valid questionnaires retrieved, 74.3% of parents reported using generic drugs for young patients. Approximately 92.2% of the parents reported using the children’s medical expense subsidy system. The highest (51.4%) reason for switching to generics was “recommendation from a pharmacist, etc.” Cognitive methods using online content were higher among male parents than among female parents (28.0% vs. 11.5% ; P<0.001). Regarding catchphrases that make them want to hear, female parents were more likely to hear about generic drugs than male parents were if the catchphrases quality and safety were used (38.1% vs. 23.8% ; P＝0.007). Compared to parents of 7-19-year old children (6.8%), parents of 0-6-year old children (13.1%) reportedly switched to generic drugs because they were easier to ingest (P＝0.022). Conclusion: Recommendations from medical professionals such as pharmacists are effective in convincing parents of young patients to switch to generic drug use. To promote the use of generic drugs in young patients, in addition to explaining and publicizing its financial benefits, pharmacists need to explain the added value of generic drugs such as the ingenuity of its dosage form. In addition, it is essential to adopt a multifaceted approach that considers the parents’ background including (1) publicity using the internet for male parents, (2) reaching out to female parents with preschool children, (3) increasing publicity using tickets for children’s medical expenses subsidy system, and (4) drug education that matches the growth of children.</p>