Regeneration of Periodontium with PRP does not only improve regeneration rate and density of bone but have a possibility to estimate faster healing process for soft tissue. And also, synthetic bone and xenogenic bone graft are effective on regeneration of periodontium. The purpose of this study is to evaluate the effectiveness of synthetic bone ($Biogran^{(R)}$) and xenogenic bone ($BBP^{(R)}$) grafts with the PRP technique on regeneration of periodontium. 52 Generally healthy Pt. who had pocket depth 5mm at any of 6 surfaces of the teeth were in the study at Dept. of Perio. in Dankook Dental Hospital. Open Flap was treated for 18 infra-bony pockets as control group, $Biogran^{(R)}$ with PRP was inserted for 25 infrabony pockets as first test group, and $BBP^{(R)}$ with PRP was inserted for 22 infrabony pockets as 2nd test group. Then evaluation was made after 3 and 6 months 1. 6 months after surgery, each difference of average probing pocket depth was $2.61{pm}0.23$ for control, $3.40{pm}0.30$ for 1st test, and $3.45{pm}0.37$ for 2nd test group. 2. 6 months after surgery, each difference of clinical probing attachment level was $1.39{pm}0.12$ for control, $2.88{pm}0,24$ for 1st, and $2.86{pm}0,27$ for 2nd test group. 3. 6 months after surgery, each difference of Maximal probing attachment level was $1.11{pm}0.16$ for control, $3.28{pm}0.30$ for 1st, and $3.27{pm}0.35$ for 2nd test group. 4. There were significant differences for clinical change of each three group which were between average probing pocket depth and clinical attachment level of 3,6 months and minimal and maximal attachment level after 6 months 5. There were significant differences for average probing pocket depth which were only at control group and 2nd test group between 1 and 6months. For clinical attachment level and minimal and maximal proving attachment level, there was a significant difference after 6month of surgery. 6. There was no significant difference between two test groups for average probing depth, clinical attachment level, and minima1 and maximal probing attachment level. As the result, PRP with bone graft is very effective for regeneration of periodontium and there is no difference between xenogenic bone and synthetic bone.