Binder-free multi-walled carbon nanotube (MWCNT) blocks from fluorinated MWCNTs were prepared using thermal heating and a compression method in vacuo. The resulting carbon nanotube blocks are lighter than graphite, can be machined and polished, possess average bending strengths of 102.2 MPa, a bending modulus of 15.4 GPa, and moderate wettability. The binder-free MWCNT blocks possess good biocompatibility when tested in the subcutaneous tissue of rats in vivo, which were covered by thin granulation tissue, 40-70 μm in thickness, comprising a few lymphocytes, cell with large cytoplasmic spaces like fibroblasts and foreign-body giant cells. That is indicative of a slight inflammatory response than MWCNT/resin blocks and poly(methyl methacrylate). This material can potentially be employed as an alternative artificial hard tissue or internal bone plate that makes use of the properties of CNTs.