Two fully dense composites containing AlN, SiC, and MoSi2 in different amounts were produced by hot pressing. Young modulus, hardness, electrical conductivity, and thermal expansion coefficient were measured at room temperature. Strength and toughness were evaluated up to 1300degreesC in air. According to statistical analysis, the temperature has little or no effect on high-temperature fracture behavior of the composites. These electroconductive materials are suitable for thermomechanical applications at high temperature, the strength being about 600 MPa at 1300degreesC.