This research aims to investigate the effects of thyroidectomy on fracture healing. The experiment included sixteen male rabbits which allocated randomly into two equal groups. Rabbits anesthetized by premedicated atropine sulphate, then 15 minutes later, a mixture of Xylazine Ketamine was used. The control group rabbits were induced with mid-shafted femoral fracture, with that, it fixed firmly by intramedullary pinning. Meanwhile, the treated group rabbits were induced with same method mentioned above, but fracture were fixed after thyroidectomy and investigation of thyroxin a week postoperatively. In control group results involved sever inflammatory reaction as compare to treatment group. The signs of inflation subsided gradually during 4-5 days in treatment group, whereas, it took 5-6 days in control animals. Also, radiological investigation of both groups exhibited periosteal reaction which was observed at end of 2 nd week in the control group, whereas, the treated group showed its reaction at the end of fourth week, there was an invisible fracture line for both control and treated groups at the end of fourth and sixth week, respectively. In addition, bony bridge in the control groups became remodeled into a lamellar bone earlier than treated group. The results of measuring thyroxin hormone before and after the thyroidectomy confirmed the essential role of this hormone in fracture healing. To conclude that the fracture healing maturity was superior in control group than in treated group.