Background: The conventional standard treatment approach for thyroid cancer has been complete thyroidectomy with or without radioactive iodine (RAI) ablation, followed by thyrotropin suppression. Levothyroxine has been advocated for TSH suppression to prolong survival and decrease tumor recurrence, particularly in high-risk patients. Objective: This study was aimed to compare the effect of high dose (ablative dose) and low dose (therapeutic dose) of levothyroxine on bone density, calcium levels and Vitamin D levels. Patients and Methods: This retrospective and prospective cohort study included a total of 100 patients presented with thyroid disorders, attending at Department of the General Surgery and Out-Patient Clinic of Endocrine Surgery Unit, Mansoura University Hospitals. This study was conducted between November 2020 and the end of April 2022.  Results: The post thyroidectomy levothyroxine dosage had statistically significant effect on results on bone mineral density especially in ablative dose of levothyroxine which has osteoporotic effect. There was no significant difference between calcium levels and Vitamin D levels preoperatively between therapeutic and ablative dose while there was correction of calcium levels and vitamin D levels post operatively in therapeutic dose while in ablative dose there was a decrease in average results of serum calcium and vitamin D levels after 6 months. Conclusion: It could be concluded that the high dose of levothyroxine which is considered as ablative dose of post thyroidectomy hypothyroidism due to differentiated thyroid cancer have adverse effectson metabolic profile regarding calcium and 25 hydroxyl vitamin D which may carry hazards of bone mineral density regarding osteopenia and osteoporosis.