This article describes two cases of severe persistent hypocalcemia occurring despite vitamin D and calcium supplementation in children with symptomatic vitamin D deficiency. We compared these cases with hungry bone syndrome (HBS) occurring after parathyroidectomy. Studies of hypocalcemia due to vitamin D deficiency suggest a potential risk of hungry bone (HB)-like syndrome if calcium treatment is inadequate at the start of vitamin D supplementation. This article highlights the pitfalls of hypocalcemia management. Hypocalcemia should be actively treated with calcium boluses and continuous infusion to avoid the possibility of HB-like syndrome.