Copper reinforced with low Coefficient of Thermal Expansion (CTE) fillers such as carbon fibers or SiC particles have been investigated for several years. Such a material combines a high thermal conductivity with a low CTE. This work reports on first results which have been achieved by combining a copper matrix with a filler material exhibiting a negative CTE by using rapid sintering with the goal to reduce the resulting overall CTE but keeping a high thermal conductivity at a relatively low amount of filler. The used filler material is characterized by a negative CTE value in the range of -8 to -10 ppm/K. By using a powder metallurgical approach whereby mixing Cu with the negative filler a composite with tailorable CTE can be prepared. The produced composites have been investigated with respect to their thermal expansion behavior. A promising material with a CTE in the range of 8 to 12 ppm/K at room temperature and still acceptable thermal conductivity has been obtained.