Sandwich composite structures are used in many fields of engineering especially aerospace engineering. They have the advantage over traditional materials of exceptional properties in regards to stiffness combined with very low specific weight. In the case of sandwich composites with honeycomb cores the occurrence of air bubbles in the resin that binds the core and the fibre sheets together has been observed after the curing. These bubbles weaken the connection between core and fibre layers locally and the overall integrity of the composite. It is assumed the source of these bubbles is an overpressure of the air inside the cells of the core which occurs during curing. As such engineers are interested in measuring this internal air pressure during curing in order to verify this assumption and to develop measures to counteract the creation of air bubbles. During the course of this work it was researched how to facilitate such measuring and which sensors are capable of doing so. Furthermore experiments with suitable sensors in measuring the internal pressure of sandwich composite structures with a honeycomb core were done.