Abstract: A pressure sensing device having a separator diaphragm through which pressure is transmitted from a working fluid to a liquid within a first part of the device and a transducer for measuring the pressure of the liquid or the difference between the pressure of the liquid and the pressure of an external fluid. A pressure overload diaphragm comprises a dished plate which forms part of a side wall of the first part of the device and has an inner section of the plate extending inwardly of that part. The overload diaphragm is inflexible or substantially inflexible over a working range of differential pressures applied thereto but the inner section thereof moves outwardly of the first part of the device if the differential pressure exceeds a predetermined value.