A plurality of hydrostatic weight sensors, each incorporating a fluid and a pressure sensor for sensing the pressure thereof, are incorporated in a vehicle seat to sense occupant weight, position, and stature. In one aspect, a hydrostatic weight sensor is located in the seat back and a separate hydrostatic weight sensor is located in the seat bottom. In another aspect, a plurality of laterally or longitudinally proximate hydrostatic weight sensors, or a single bladder with a plurality of chambers, is incorporated in the seat bottom to sense occupant position. In another aspect, a hydrostatic seat weight sensor is provided by forming a fluid filled cavity within a seat cushion and sensing the pressure of the fluid therein. A signal processor calculates the occupant weight, position, and stature from the respective pressure sensor output signals and controls a safety restraint system responsive thereto.