Metal Injection Molding (MIM) is characterized by its ability to accommodate complex shapes, achieve high density, offer a wide range of material choices, and facilitate mass production. Despite these advantages, there has been a recognized challenge in addressing the production of hollow parts. To meet market demands, we have embarked on the development of integrated three-dimensional hollow shapes that were previously unattainable. We have now successfully achieved mass production of hollow MIM parts. This paper introduces the hollow MIM process, along with its issues and countermeasures.