Background: Studies have shown that bioactive cements have beneficial bone-forming effects. Our objective in the present study is to investigate the efficacy of tetracalcium phosphate (TTCP) on fracture healing in rat femur.Materials and methods: Forty-two female Wistar Albino rats randomized into two groups (groups 1 and 2, n=21 for each). The left femur of all animals was fractured by osteotomy after deep anesthesia with ketamine. Additional procedure was not applied to the rats in group 1. Rats in Group 2, following osteotomy were applied to the fracture line approximately 2 cc TTCP. The animals were sacrificed on the 1st, 2nd and 3rd post-operative weeks (each week 7 animals were sacrificed from each group) and the broken femur were removed. The femur were examined first radiographically and second, histopathologically.Results: Radiologically, callus maturity and bone union increased with time in both groups. But no significant differences were found regarding callus maturity and bone union in weekly comparisons (Anteroposterior plain: p:0.53, p:0.37, p:0.42, Lateral plain p:0.26, p:0.42, p:0.87). Histopathologically, the fractures healed normally as the weeks progressed in both groups. In the comparison of both groups, no significant difference was found outside the 1st week, although the histological scores of group 2, who were treated for all weeks, were higher in terms of fracture healing (p:0,024, p:104,p:462).Conclusions: Although no significant difference was found in the comparison of both groups except for the first week, the histological scores of the group 2 who received TTCP in all weeks were higher in terms of fracture healing. According to the results of this study, we think that TTCP can be useful especially in the early stages of fracture healing.