Biotechnology, in conjunction with semiconductor and microelectronics, would have a tremendous impact on new solutions in gene and drug discovery, point-of-care systems, pharmacogenomics, and environmental and food safety applications. A combination of microfabrication techniques and molecular biology procedures have the potential to produce powerful, inexpensive, and miniature analytical devices (e.g., microfluidic lab chips), aiding further development of genetic analysis. Microfluidics for biotechnology applications require development of inexpensive, high-volume fabrication techniques and reduction of biochemical assays to the chip format. We discuss design, fabrication, and testing of plastic microfluidic devices for on-chip genetic sample preparation and DNA microarray detection. Plastic microfabrication methods are being used to produce components of a complete microsystem for genetic analysis. A detailed discussion on the development of micromixers, microvalves, cell capture, micro-polymerase chain reaction (PCR) devices, and biochannel hybridization arrays is given. We also describe a path to further individual component integration.