Calcium alkali syndrome (CAS), a relatively unusual etiology of hypercalcemia, is characterized by a classical triad of hypercalcemia, azotemia, and metabolic alkalosis. This condition has been described in patients who have taken an excess dose of calcium with an alkali or with a volume-depletion status. To diagnose CAS it requires a high index of suspicion and a detailed history of medication/supplement intake specifically for calcium-containing drugs and a history of all possible ingested alkali. We reported a case of post-surgical hypoparathyroidism whom later on was presented with hypercalcemic crisis due to CAS. The proposed mechanism of CAS and management are also included.