Koiki Mombetsu Hospital is a hospital specializing in internal medicine, located in Ochiishi-cho, Mombetsu City, Hokkaido. The hospital is jointly operated on a wide-area cooperative basis by five municipalities — Mombetsu City, Takiue Town, Okoppe Town, Nishiokoppe Village, and Oumu Town — and is known as the core facility for regional healthcare in the western Okhotsk Mombetsu area. A defining feature of this institution is its wide-area cooperative management structure that extends beyond a single municipality, supporting stable medical provision throughout the region. The hospital offers internal medicine services, addressing both the everyday health management and treatment of illnesses for local residents. The facility provides multilingual support in English, Korean, and other languages, creating a welcoming environment for people of diverse backgrounds. The building is barrier-free, allowing wheelchair users and those with physical disabilities to visit with confidence. A dedicated parking lot is also available, making access by car convenient. The hospital is closed on Saturdays, Sundays, public holidays, and during the year-end and New Year period (December 29 to January 3). Serving the vast medical needs of the Okhotsk coastal area, this hospital continues to support the health of local residents through community-focused internal medicine care.