The aim of this study was to examine the effect of salmon calcitonin on histopathology and radiography of the fracture repair.Transverse mid-diaphyseal fracture of the right tibia of the 48 Wistar rats were surgically induced and stabilized by intramedullary Kirschner wires. The rats were arbitrarily assigned to four groups of 12 animals each. Group I and II were the control groups and did not receive any medication; the other two groups of rats received 20 mg/ kg/day salmon calcitonin intramuscularly for 6 weeks (Group III) and for 10 weeks (Group IV) postoperatively. Formation and healing of bone were determined by radiography and by histopathological examination . Results of the radiographic examinations were evaluated by using Lane-Shandu scoring system and the results of the histopathologic examinations were evaluated by using HUO scoring system.  Radiography and histopathology demonstrated normal bone healing at the fracture site in all rats. On radiographic examination, there were no statistically significant differences between two groups at 6th week and 10th week evaluations. Results of the histopathologic examinations were statistically significant in calcitonin group at the early stage (6th week) of the fracture healing (p<0.05), but there were no statistically significant differences between two groups at the 10th week evaluations. Better histopathologic results at the early stage of the fracture healing might imply that calcitonin has beneficial effects on fracture healing at the earlier stages of the healing process. These findings encourage earlier ambulation and weight bearing in such cases with previous surgical history of internal fixation.