Purpose: The purpose of this study is to evaluate the effect of exposure of hydroxyapatite coating on the amount of bone formation and stability in the dogs. Methods: In this study, hydroxyapatite coated implants (HAPTITE) was placed over the femur bone surface of four dogs about 1 mm. The experimental group was divided into 4 weeks group of 8 implants and 8 weeks group of 8 implants, and then they were sacrificed. The stability of implants was evaluated twice with Osstell$^{TM}$ mentor (Osstell AB, Goteborg, Sweden) at right after placement and sacrifice. The amount of bone formation was evaluated through histomorphometric examination. Results: The stability of implants was in normal range, and tended to increase as time goes by. Mean percentages of new bone formation rates were $90.5{pm}6.6$ at uppermost 1 mm bone level adjacent to soft tissues (level 1) and $92.9{pm}4.1$ at next 1 mm bone level (level 2) in 4 weeks group, $90.1{pm}11.5$ at level 1 and $95.9{pm}2.3$ at level 2 in 8 weeks group. Mean percentages of bone-implant contact rates were $85.1{pm}10.8$ at level 1 and $88.1{pm}13.8$ at level 2 in 4 weeks group, $88.5{pm}14.4$ at level 1 and $95.3{pm}3.1$ at level 2 in 8 weeks group. There was no statistically significant difference of new bone formation rate and bone-implant contact rate between uppermost 1 mm bone level adjacent to soft tissues and next 1 mm bone level. However, there was no significant difference in bone formation between 4 and 8 weeks groups. Conclusion: These results suggested that exposed hydroxyapatite coated implants to soft tissue showed favorable bone formation and implant stability.