Parathyroid carcinoma is a very rare cause of hyperparathyroidism. The diagnosis is usually established on histopathological grounds of capsular and vascular invasion, but a potential clue to the diagnosis is also offered by the severity of clinical profile, abrupt onset of symptoms, and a high degree of hypercalcemia and raised serum parathyroid hormone (PTH). We report a case of an elderly female with a prolonged history of generalized weakness and bone pain along with bilateral renal calculi, classical bony lesions, and a high serum calcium and PTH level who underwent a right inferior parathyroidectomy considering a parathyroid adenoma as our diagnosis. However, the biopsy report was consistent with a parathyroid carcinoma, and so, she was further subjected to an ipsilateral hemithyroidectomy as a completion procedure. So, we would like to emphasize that its preferable to have a high index of suspicion for parathyroid carcinoma when these clues are present, than to miss the opportunity for surgical cure in the first go by failing to consider it in the differential diagnosis.