The science of pressure measurement is mature with many available pressure measurement technologies some of which have their origins dating back to steam power and the industrial revolution. Along with temperature, the use of pressure as a general physiological parameter is well established and it may be accurately and reliably determined for a wide range of medical applications and environments involving liquids and gases (Mootanah & Bader, 2006). However, pressure is also commonly used in biomedical engineering and medicine to quantify the mechanical interaction between biomedical interfaces such as those arising between tissue and support surfaces (Tissue Viability Society, 2010; Shelton et al, 1998), e.g. beds, seats, prosthesis, and between tissue and pressure applying devices such as tourniquets (Doyle & Taillac, 2008), bandages (Partsch et al, 2006), and surgical instruments. The term interface pressure may be used in such contexts. The materials constituting such interfaces are, in general, not fluidic but connective and so they may support shear and torsional forces in addition to the normal hydrostatic force quantified as pressure/interface-pressure (average normal force per unit area). The non-fluid nature of many biomedical interfaces means that current mature quantitative pressure measurement technologies are not well matched to the biomedical interface environment, i.e. they are not media compatible. Pressure measurement devices may also contribute to erroneous and anomalous data since they need to be deployed at the interface site and so are necessarily intrusive (Casey et al, 2001; O’Brien & Casey, 2002). These problems have acted as a barrier to the more general use of pressure measurement to characterise mechanical interactions at biomedical interfaces. In cases where such measurements have been used, the resulting data is often degraded due to interface and sensor contact artifacts ultimately leading to difficulties with reproducibility and reliability (Buis & Convery, 1997; Fay & Brienza, 2000). Significant benefits would arise if a reliable low cost interface pressure measurement technology were available for emergency, acute and home medical care environments as well as areas such as Intravenous Regional Anaesthesis (Casey et al, 2004), compression therapy and pre-hospital emergency care. Such a technology would allow improved diagnostics and treatments, early hazard warning and could save lives (Kragh et al, 2009; Noordin et al, 2009). In this chapter, modifications to readily available MEMS devices are described which render the devices suitable for general purpose non-invasive pressure and pressure gradient measurement at biomedical interfaces. Sample data is presented for a range of biomedical application environments including pneumatic and non-pneumatic tourniquets, bandages Pressure Measurement at Biomedical Interfaces