This case highlights the role of calcitonin in the follow-up and management of thyroid medullary carcinoma. The progressive rise in the serum calcitonin level during the postsurgical follow-up in a 48-year-old male led to his hospitalization, and procedures like CT scan and isotope bone scan established MTC recurrence with metastasis. He was given palliative care with tyrosine kinase inhibitors. There is elaborate discussion on the nature of thyroid malignancies, presentation and management of MTC, and the conditions associated with the high calcitonin level.