Many activities over the last five or so years have focussed on the thus far underdeveloped field of carrying out reactions on small scales. Due to the rapid development of new components, this paper touches on recent developments only in a compressed form. An important point is the analysis of possible plant concepts for microreactors and whether these are a sensible option. Due to the enormous size difference between the microchannels and the fluid periphery of possible components this is not just a technical question, it touches on the microtechnology concept as a whole. The direction in which the field should be developed and which measures can be taken to influence its development, are questions that are addressed here with respect to the big industrial interest in microreactors.