Piezo-driven microdispensers, i.e. micropumps and microvalves, can dose minute volumes down to the microliter range with high accuracy. Disk-shaped piezo elements by PI (Physik Instrumente) LP, Auburn, MA, mounted directly onto a metal microdiaphragm provide the precision drive for miniature liquid or gas pumps. Interference with the pumped media is avoided, due to the separation of the drive and medium through the diaphragm. Lab-on chip applications are made possible by the minute dimensions.