Hypertension is a relatively common occurrence during pregnancy, which usually has a benign course with an excellent prognosis. However, physicians caring for pregnant women should have a high index of suspicion for underlying medical conditions that could lead to a more perilous outcome. Herein, we present the case of a pregnant woman who was found to have uncontrollable hypertension late in her pregnancy, secondary to a mediastinal pheochromocytoma, which was deemed unresectable at the time of exploration after her delivery.