We report a donor death after right hepatectomy for living donor transplantation due to an undiagnosed myeloma. The 47-year-old donor, who was the 147th case performed in our department, was in excellent health without any abnormalities in the preoperative investigations. Despite an uneventful right hepatectomy without transfusion, the patient developed a partial thrombus of the inferior vena cava with a right proximal pulmonary trunk embolism on postoperative day 6. Subsequently, he developed multiorgan dysfunction leading to a coagulopathy, respiratory distress, and renal failure requiring hemodialysis and mechanical ventilation. This clinical scenario led us to suspect a hematological disorder. Immune electrophoresis showed a monoclonal peak of immunoglobulin G (8.7 g/L), a myelogram revealed an abnormally high level of dystrophic plasmocytes (more than 7%), and biopsies of salivary glands confirmed the diagnosis of immunoglobulin G kappa myeloma. The patient progressively deteriorated because of simultaneous hemorrhagic and infectious pulmonary complications resulting in septic shock. Despite an adequate combination of antimicrobial therapy and pleural drainage, the donor died on postoperative day 57 from multiple organ failure. This unusual cause of donor death after right hepatectomy reinforces the need for an extensive preoperative assessment. We advocate the addition of urinary protein loss and electrophoresis to the standard donor assessment protocol.