The tribological behavior of surfaces depends on a number of factors including hardness, elasticity, fracture toughness, adhesion and oxidation rate. Many of these are determined unambiguously by the composition and microstructure. The ultimate way to modify the microstructure is a refinement of the grain size down to the nanometric scale. This results in an increase in hardness and fracture toughness, among other changes. The microstructure and mechanical properties of MoSi2/SiC nanocomposites have been reported elsewhere. The wide variety of microstructures of this system with a constant nominal composition provides an excellent opportunity to examine the effect of ultimate microstructure modifications on tribological behavior. In this work we used a pin-on-disc test in a controlled humidity of 50% and a steel pin as a counterface to investigate the dry sliding properties of MoSi2/SiC nanocomposites with two different microstructures. For comparison, single layers of MoSi2and SiC were examined. The results are discussed in terms of the hardness and elasticity.