It has been known for many years that the incorporation of metallic particulates into a ceramic matrix can bring about improvement on ceramic mechanical properties, but little is known how the addition of metallic particles into a ceramic base affects the thermal shock resistance of this sort of material. The present work is concerned with the thermal shock behavior of an alumina base ceramic matrix composite containing 5vol% of copper particles. The composite, hot-pressed at 1550 degreesC, exhibited increased thermal conductivity, enhanced toughness, decreased modulus and higher resistance to thermal shock compared with monolithic alumina. Some mechanical and thermal properties relevant to thermal shock are discussed which give plausible explanations for the differences between the composite and the monolith.