A multi-step process to fabricate a diamond single crystal that is larger than the original, natural, commercially-obtained crystals is described. Starting with 3.0 mm X 3.0 mm X 0.25 mm, natural, type Ia C(100) crystals that have had their edges oriented to (010) and (001), we have successfully bonded two to a Si substrate in close proximity to each other. Subsequent diamond homoepitaxy using plasma-enhanced chemical vapor deposition of up to similar to 75 mu m thickness has enabled epitaxial overgrowth to join the two diamonds. The topography was excellent, and microRaman spectroscopy indicated only a 0.6 cm(-1) line broadening (crystal degradation) at the joint. The creation of etch pits (via oxidizing flame) on the joined diamond surface indicated a higher defect density at the joint, but this more-defective region was constrained to within the dimensions of the original gap between the diamond crystals. These results indicate that this process of epitaxial joining of diamond single crystals has the potential to be scaled up to larger area in order to fabricate a diamond single crystal of desired area and reasonable crystal perfection.