The application of microtechnology to biotechnology and biosensing has rapidly expanded in response to recent advances in molecular biology and biochemistry. Gene sequencing and drug discovery have created viable commercial markets for lab-on-a-chip and other miniature, high throughput, and/or low sample volume, analysis instruments. At UCDavis, scientists and engineers are utilizing the special capabilities of microtechnology, e.g. small feature size, reproducibility, parallel processing, and multi-functionality, to realize miniature instruments for biomolecular sensing and analysis. Photonic measurement techniques are being exploited for their demonstrated superior sensitivity. Several different types of photonic microinstruments for biomolecular analysis have been designed, fabricated and demonstrated, including a surface plasmon immunosensor, a multichannel combinatorial. bead analyzer, and a DNA quantification microinstrument. A brief description of their function, microfabrication, assembly, and testing are presented.