This study aimed to evaluate the efficacy of calcium carbonate nanoparticles (CCNPs) and Silver nanoparticles (Ag NPs) to induce new bone formation and accelerate bone regeneration when be used to fill an experimentally critical defect in the radial bone of rabbits. 24 adult apparently healthy New Zealand white rabbits aged from 5-6 months and weighing 3.5 ± 0.5 kg were used in this study and were divided into two groups, group A: we used CCNPs paste only. Group B: we used CCNPs/Ag NPs paste. During the observation period, rabbits were observed clinically and radiographically at 2,4,8,12 weeks post-operation. Results: the total radiographic score showed that there was a significant difference between groups (A) and group (B) at the eighth postoperative week and at the period of observation (12 weeks) while there was no significant difference at second and fourth post an operative week. Conclusion: radiographical studies revealed that CCNPs and Ag NPs have the ability to induce new bone formation and CCNPs/AgNPs paste was able to make relatively complete healing at the end of the observation period.