Several hospitalized patients have a history of medication use; consequently, there are numerous reports on the importance of pharmacists managing their own medications. Conversely, there is a lack of information about the status of patients medication adherence. Therefore, we collected data on medicines brought to hospital by inpatients and investigated their medication compliance status. The medication compliance status of patients visiting the Kokuho Chuo Hospital from April 2017 to March 2018 was investigated using the identi cation sheets of medicines brought by these patients and patients medical records. The number of differentiations of medicines brought to the hospital by inpatients was 1,080, and the details of 889 medicines were used in this study. The average number of medicines brought per patient was 5.6 3.5, with elderly patients bringing more medicines and exhibiting a low medication compliance. Compliance with antibiotics, chemotherapeutics, and oncology drugs was good, whereas that of vitamins, peripheral nervous system agents, and drugs for treating sensory organ issues was poor. The cost of medication per patient among nonadherent patients was approximately 3,836 11,078 yen, amounting to a total cost of 3,409,914 yen. The medication compliance status inferred from this study was worse among elderly patients as well as for medicines used to treat chronic diseases. Pharmacists can provide appropriate drug treatments and contribute toward reducing healthcare costs by increasing awareness regarding the family pharmacist system and improving cooperation between community pharmacies and hospitals to improve polypharmacy and medication adherence.