Aim: To emphasize the importance of vitamin D supplementation. Background: The incidence of vitamin D deficiency has been increasing worldwide, probably due to decreased exposure to sunlight and unbalanced diet. Severe hypocalcemia following vitamin D deficiency is rather uncommon, and this leading to seizures in adults is a rare scenario. Case description: This is the case of a 70-year-old female, a known case of coronary artery disease, who presented with one episode of seizure. Computed tomography of her brain revealed diffuse age-related atrophic changes, and electroencephalogram showed diffuse cerebral dysfunction. She was found to have severe hypocalcemia with secondary hyperparathyroidism due to vitamin D deficiency. Vitamin D bolus was given along with calcium correction, following which she improved. Conclusion: There are a few reports of hypocalcemic seizures among children; however, the incidence is rare among adults. Calcium and vitamin D supplementation forms the mainstay of treatment. Clinical significance: Hypocalcemic seizure is uncommon, especially among adults. Vitamin D deficiency resulting in hypocalcemic seizure, to the best of our knowledge, is an unreported scenario. This case highlights the importance of vitamin D supplementation in those with reduced sunlight exposure.