In the present work, a 2124/15 vol%MoSi2 composite was obtained by powder metallurgy. Its microstructure and mechanical properties were investigated at room and at high temperature (up to 200 degrees C) in conditions T351, T4 and after heat treatments at 495 degrees C for up to 100 h. Up to 150 degrees C, tensile properties of 2124/MoSi2 in T351 resulted similar to those of a ceramic reinforced 2124/SiC composite. Yield stress of the 2124/MoSi2 material, after heating at 495 degrees C for up to 100 h, resulted higher than that of the monolith 2124 alloy heated for the same periods. No diffusion reaction phases were formed surrounding the MoSi2 reinforcing particles during such long exposures to high temperature. Only at 100 h, large plate-like precipitates that contain Al, Cu, Mg and Si appeared. The high thermal stability of this 2124/MoSi2 composite and its good mechanical properties at room and at elevated temperature makes MoSi2 intermetallic a competitor of ceramic reinforcements. (c) 2006 Springer Science + Business Media, Inc.