The use of microfluidic bioreactor platforms for cell culturing holds considerable promise for a range of fields which include drug discovery, tissue engineering, bioprocessing optimisation and cell based screening studies. Microfluidic bioreactor systems have length scales that are well matched to the physical dimensions of most cells and microorganisms. In view of this, microfluidic bioreactors have attractive features which make them ideal to study the behaviour of cells and their internal organisation in their native microenvironment. Due to their small footprint microbioreactor platforms offer a number of advantages over conventional macroscale systems including improved biological function, higher quality cell-based data, reduced volume of reagents, ease of integration and lower cost. This review highlights the basic concepts, designs and operational requirements of microbioreactors for cell based studies. An illustrative outline of different applications of microbioreactors and some indication of new trends and progress in recent years are provided. Specific examples of applications of microbioreactors are drawn for cytotoxicity assays, tissue engineering, stem cells, microbial fermentations, single cell analysis and in vitro fertilisation.