Background: Hypocalcemia, a condition where the serum calcium concentration or total serum calcium is below normal, could be associated with various manifestations including severe symptoms requiring immediate hospitalization. The condition can cause by several causes including iatrogenic thyroidectomy. Here, we report a patient of hypocalcemia associated with hypoparathyroidism due to post-thyroidectomy. Case presentation: A 32-year-old woman admitted to the hospital complained of stiffness and tingling in the extremities accompanied by recurrent seizures. The serum calcium level was low and this hypocalcemia condition was associated with low parathyroid hormone levels after subtotal thyroidectomy surgery. Laboratory examination indicated calcium 4.8 mg/ dL and parathyroid hormone 2.21 pg/ml. The patient had bradycardia with prolonged QT on electrocardiography (ECG) and developed cataracts in both eyes which could be associated with chronic hypocalcemia. The patient’s condition improved after correction of hypocalcemia. After discharge, the patient was given calcium and levothyroxine supplementation due to hypothyroid conditions. Conclusion: The hypocalcemia condition in the patient was associated with low parathyroid hormone level post-subtotal thyroidectomy surgery. This case highlights the impotence of detailed analyses of hormonal, radiological and histological investigations of patients with thyroid gland diseases to diagnose such conditions early and to ensure timely management.