In order to fabricate microsensors, a micromachining, microfabrication technique based on LSI technologies has been used. In this paper, useful micromachining techniques are described. Examples of integrated microsensors, such as a pressure sensor including a readout circuit and a multisensor cell for blood gas analysis, are introduced. Microflow control devices, such as microvalve and a micropump for integrated chemical analysis systems, are also described.