Hypocalcemia associated with labor and lactation is a rare condition reported previously in patients with hypovitaminosis D. We here describe a case of a young woman in whom symptomatic severe hypocalcemia appeared after her second delivery, early in lactation. At the end of lactation the condition worsened. We review all previously reported cases and suggest a possible physiologic explanation for the association between pregnancy, lactation and the appearance of symptomatic hypocalcemia.