Mixed medullary-papillary carcinoma of the thyroid, a variant of medullary carcinoma is a rare thyroid malignancy accounting for less than 1% of the thyroid malignancies. We are presenting a case of 57-year-old lady with complaints of gradually increasing thyroid swelling for 1½ months. Fine-needle aspiration was suggestive of medullary carcinoma. Serum calcitonin levels were elevated. The patient underwent total thyoidectomy with regional cervical lymph node excision. Histopathologically, the diagnosis of mixed medullary-papillary carcinoma of the thyroid was made. It is important to know about this entity due to its prognostic implications and to prevent any diagnostic dilemmas.