A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is being developed to monitor the structural integrity of components employed in advanced aerospace propulsion systems that operate at temperatures in excess of 1500?C. Electrical and chemical stability is particularly critical in these harsh environments, since these ceramic strain gages must survive tens of hours of strain testing at elevated temperatures. SEM micrographs of the surfaces of these strain gages after high temperature exposure revealed a partially sintered microstructure consisting of a contiguous network of nano-sized ITO particles with well defined necks. Electrical conduction along the surfaces of these contiguous ITO particles resulted in a very stable and large piezoresistive response at temperatures as high as 1575^oC. It appeared that densification of the ITO particles was retarded during high temperature exposure with nitrogen playing a key role in stabilizing the nanoporosity. To prepare this nanoporous ITO, sputtered ITO films were subjected to a post deposition anneal at 700^oC in nitrogen and subsequently exposed to high temperature. Based on these preliminary results, ITO strain sensors were reactively sputtered in various nitrogen/oxygen/argon environments. SEM and AFM indicated that although the microstructures of these nitrogen-sputtered films were similar in appearance to those produced by a post deposition anneal in nitrogen, the average pore size and particle size were an order of magnitude smaller. It appears that nitrogen was metastably retained in the individual ITO grains during sputtering and diffused out of the bulk grains at elevated temperature, eventually becoming trapped at grain boundaries and triple junctions. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established. Static strain testing of the nitrogen-sputtered ITO sensors indicated that a similarly stable and responsive strain gage could be reproduced using this approach. The high temperature-piezoresistive behavior of ITO strain gages prepared with controlled nanoporosity is presented within and the potential impact on other types of ceramic sensors will be discussed.