The aim of this paper is to investigate whether and how medical informatics can claim to have a sound scientific basis. Why is such clarification fruitful? First, it provides a common ground for the core principles, theories and methods used to gain knowledge and to guide the practice. Without such a ground, medical informatics might be subsumed to medical engineering at one institution and to life sciences at another institution or might be just regarded as an application domain within computer science. We will provide a succinct outline of the philosophy of science, after which we provide an application of the related notions in order to decide the scientific status of medical informatics. We justify viewing medical informatics as an interdisciplinary field with a paradigm that can be formulated as “user-centered process-orientation in the healthcare setting”. Even if MI is not merely applied computer science, it still remains uncertain whether it will attain the status of a mature science, especially without comprehensive theories.