During the last five years, the number of patent publications in the field of microreactor engineering has increased steadily and seems now to approach a more constant level. The majority of patents are initiated by German, US, and Japanese inventors or applicants. Even among these, a few chemical companies and institutes have a major share. Initially, the focus was on fabrication, device, and total system related inventions. Meanwhile, an increasing number of process patent publications have been released showing the further stage of implementation of the technique which is moving to micro process engineering. The focus of the patents and published patent applications is on fine-chemical processes.