Objective: To study the biocompatibility of Ti-75 (TiAlMoZr). Methods: Six adult mongrel dogs received Ti-75 bars and pure titanium bars surgically in their femurs .The dogs were sacrificed at 3,6 and 12 months post-implantation, respectively. On 3rd and 14th day before their sacrifice, intramuscular injection of tetracycline had been given. The specimens that had been canceled with the implants were cut and sectioned. The bone-implant interfaces were observed under a fluorescence microscope and the photographs were taken. The fluorescence labelled areas were evaluated quantitatively by the computer image analysis system. Results: The percentage of labelled area had no difference between Ti-75 and pure titanium. There was also no difference in the three periods when same material was used. Conclusion: The biocompatibility of Ti-75 and pure titanium is similar.