In this work, metal-matrix composites which possess tunable thermal expansion coefficients in combination with high electrical and thermal conductivities were successfully synthesized by a moderate temperature hot-pressing method. The composites are based on incorporating La(Fe, Si, Co)₁₃, a material with a negative coefficient of thermal expansion, within a continuous Cu matrix. The La(Fe, Si, Co)₁₃ enables us to tune the coefficient of thermal expansion in a predictable manner, while the Cu phase is responsible for the electrical and thermal conductivity properties. The resulting materials exhibit coefficients of thermal expansion which can be tuned between the value of pure Cu and La(Fe, Si, Co)₁₃. Thus, by adjusting the relative amount of the two components, the materials can be designed with high electrical and thermal conductivities and tailoring coefficient of thermal expansion properties. This unique combination of electrical and thermal properties enables these Cu-based metal-matrix composites to be applied in the microelectronic, semiconductor and thermoelectric industries.