In the last decade micro bioreactor (MBR) technology has made rapid advances in biotechnology process development and in the investigation of various biological systems from industrial to pharmaceutical biotechnology applications. MBRs range in complexity from simple micro titer-based systems to complex automated parallel bioreactors designed to allow the meaningful scale-up/ -down of conventional pilot and large-scale bioprocesses. MBR technology and the capability to monitor cultivation process variables in situ, provide real-time and quantitative data from the microliter cultivation. This paper gives an overview of micro technologically fabricated MBRs, for the high-throughput operation, its design, advantages and current limitations and potential future challenges in different biotechnological fields.