The miniaturization of biomedical and biochemical devices for micro-electromechanical systems (BioMEMS) has gained a great deal of attention in recent years. Products include biochips/biosensors, drug delivery devices, tissue scaffolds, and bioreactors. In the past, MEMS devices have been fabricated almost exclusively in silicon, glass or quartz because of the similar technology available in the microelectronics industry. For applications in the biochemistry and biomedical field, polymeric materials are a desirable choice because of their lower cost, good processibility, and biocompatibility. Polymer micro-/nanofabrication techniques, however, are still not well developed. In this paper, we briefly introduce various BioMEMS applications, basic microfluidic principles and functions, and processing techniques for micro-/nano-scale structures.