In this study, we examined the effect of present bias(time preference) and belief about medicines on the medication non-adherence(intentional/unintentional) of patients with chronic disease in Korea. Over the course of this study, 158 patients with chronic diseases (hypertension/diabetes/hyperlipidemia) completed Delayed Discounting Tasks(DDT), Belief about Medicines Questionnaire-Specific(BMQ-Specific), and a revised Korean version of Adherence to Refills and Medication Scale(ARMS-K). As a result, it was found that present bias held a significantly positive effect on patients’ medication non-adherence, and results showed that the more present-biased the patients were, the higher both the intentional and unintentional non-adherences appeared. Additionally, results showed that belief about medicines held a significantly negative effect on medication non-adherence, with the stronger the belief about medicines, the lower the non-adherence, not merely unintentionally, but also intentionally. Finally, there were no interaction effects of belief about medicines on the relationship between present bias and medication non-adherence. Further analysis revealed, however, that concern about medicines, a subtype of belief about medicines, had an interaction effect on the relationship between present bias and medication non-adherence. Specifically, these results were shown in intentional non-adherence, but not in unintentional non-adherence. This study examined not only the belief patients hold for medicines, which has already been dealt with in pre-existing literature, but also suggests a new possibility where present bias may be a factor that may lead to the failure of medicine in-take for patients with chronic diseases. This study concludes with a final summary of these findings, a discussion of the implications and limitations of the study, and further suggestions for future studies.