This study explored the process of bone regeneration of growth factor enhanced matrix (GEM21s) in rabbit calvaria compared to beta-tricalcium phosphate (β-TCP). Twelve rabbits weighing between 3.500 - 4.000 g were subjected to three standard 8 mm in diameter defects at the parietal bone. The 36 defects in the 12 rabbits were categorized into 3 groups (each of 12 defects). Group 1: defects have been left unfilled with any substitute. Group II: defects were packed with β-TCP. Group III: defects were filled with GEM 21S. After 3 weeks, 6 rabbits (18 defects 6 from each group) were sacrificed, and the rest of the rabbits will be sacrificed at 6 weeks. The samples were prepared for histologic and histomorphometric analysis. Results of the present work have revealed that group II and Group III showed bone formation at both 3, and 6 weeks with a significant new bone formation in Group III (GEM21S) in comparison to group II, P< 0.001. Both groups showed a fast rise in the formation of new bones from 3 weeks to 6 weeks in comparison to group I. Immunohistochemical analysis showed higher COX-2 expression in the control group than group II, whereas, minimal expression was observed in GEM 21s treated defects. GEM21s demonstrated excellent biocompatibility and declared additional bone growth following a phase of healing of 6 weeks and it has the superior potential of bone reconstruction compared to β-TCP alone.