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In this paper the integration of a polysiiicon, surface micromachined, absolute pressure sensor with analog CMOS (Complementary Metal Oxide Semiconductor) signal conditioning circuitry is a cavity filled with sacrificial oxide. The evacuated cavity under the polysiiicon plate is created by removing the sacrificial oxide and sealed using reactive sealing. The pressure is sensed by a Wheatstone bridge formed from dielectrically isolated polysiiicon piezoresistors deposited on top of the polysiiicon diaphragm [4]. The integrated sensor chip is formed by interweaving a standard CMOS process with the sensor fabrication processes. All of the sensor process steps are compatible with standard CMOS processing A total of 17 mask steps is required for both the sensor and the signal conditioning electronics, including a passivation layer over the CMOS electronics. The sensor and the signal conditioning electronics have been fabricated on a prototype die measuring 2.54 mm on a side.