Statement: Total temporomandibular joint reconstruction is the last option for many patients with severe temporomandibular joint disease. We propose that a diamond coated implant articulation could lead to better wear properties of these devices. This animal study is one part of the biocompatibility testing of a new diamond coated biomaterial. Prior materials science and biomaterials development studies have shown diamondlike materials to be resistant to articulating wear and thereby debris generation. Development of this coating could lead to better designs, biocompatibility, and clinical longevity of these devices. Materials and Methods: Twelve round titanium discs were processed in a helium rich environment with a diamond coating along one side and titanium alloy on the other. These implants were surgically inserted into the left distal femur and proximal tibia of six rabbits, following animal resources protocols for surgery. The discs were oriented with the diamond coating posterior. After eight weeks of implantation, the rabbits were euthanized and the left leg disarticulated and preserved in formalin. Method of Data Analysis: Multiple sections were ground to 20 micrometer thickness along the implant discs. After staining with Sanderson bone stain, histomorphometric analysis was performed. Measurements taken included percent bone contact on the diamond coated side, the alloy side, and the ends, plus both quality and quantity of bone and the histological quality of the bone and marrow. Evaluation for any adverse clinical reactions was also considered. Results: A critical aspect of in vivo biocompatibility studies is the use of a standardized model with highly consistent and reproducible surgical methods. All aspects of the surgery and assessment were highly controlled. Analysis of the specimens revealed osseous integration along the diamond coated and titanium sides and no adverse reactions in the adjacent bone marrow or soft tissue. Previous studies using this model on a hydrogen processed diamond disc have demonstrated the same. Conclusion: Analysis of these specimens shows biocompatibility between the diamond coated titanium, bone, and soft tissues in the rabbit model. Direct comparison and statistical analysis of the amount of bone versus diamond coating in the hydrogen versus the helium treated discs will be performed. With proven biocompatibility, further development of this biomaterial and its use in temporomandibular joint reconstruction should proceed.