Additive manufacturing (AM) is a novel technology which allows fabrication of complex geometries from digital representations without tooling. In addition, this technology results in low material waste, short lead times and cost reduction especially for the production of parts in low quantities. Current additive manufacturing processes developed for thermoplastic sandwich panels suffer from an unavoidable weak mechanical performance and low thermal resistance. To overcome these limitations, emphasis is paid in this study on direct write AM technology for the fabrication of short carbon fiber-reinforced sandwich panel composites. Sandwich panels using different infill densities with high strength (> 107 MPa), and high short carbon fiber volume (46%) were attained successfully. In parallel to the strength enhancement, these sandwich panels possessed reduced densities (0.72 g/cc3) due to their lightweight lattice core structures. The mechanical performance of the created sandwich panels was examined and compared to the unreinforced, base ink structures by performing compression tests. Successful fabrication and characterization of the additively manufactured thermoset-based carbon fiber reinforced, sandwich panels in this study can extend the range of applications for AM composites that require lightweight structures, high mechanical performance as well as the desired component complexity.