A 66-year-old woman who was a Jehovah’s Witness had massive lower gastrointestinal bleeding and subsequent hypovolemic shock, necessitating a subtotal colectomy. During the postoperative period, her hemoglobin level decreased to a low of 2.6 g/dL, prolonging her dependence on mechanical ventilation. Prudent perioperative care resulted in a successful outcome. Blood-conserving techniques are indispensable in the management of Jehovah’s Witnesses who have massive blood loss. Maximizing oxygen transport, minimizing blood loss, using a cell saver when permissible, providing optimal ventilatory support, performing tracheostomy early if prolonged mechanical ventilation is expected, and augmenting hemoglobin production with administration of iron and erythropoietin are techniques that can facilitate successful outcome in patients who refuse blood transfusion.