Vitamin K deficiency is a common occurrence in the surgical and intensive care unit population, but its incidence in kidney and combined kidney-pancreas allograft recipients has not been described. We report four patients who received cadaveric kidney or combined kidney-pancreas allografts and subsequently developed significant bleeding associated with deficiency of vitamin K. Their coagulopathy promptly resolved with the parenteral administration of vitamin K. Treatment with vitamin K should be considered in kidney or combined kidney-pancreas allograft recipients with a prolonged prothrombin or partial thromboplastin time during the first postoperative week to avoid hemorrhagic complications.