Osmotic nephrosis with acute kidney injury can follow the administration of colloid volume expanders and other hypertonic solutions. In the kidney transplant setting, such agents may be used in the donor before organ procurement and in the recipient during the perioperative period. We report a case of acute lung and kidney injury after infusion of dextran 40 immediately after surgery in a kidney-pancreas transplant recipient. Osmotic nephrosis was confirmed by kidney biopsy, and a spectrophotometric assay was used to measure dextran 40 levels in serial serum samples. Plasmapheresis was initiated to decrease dextran 40 levels. Post hoc analysis confirmed that a single session of apheresis was sufficient to rapidly decrease dextran 40 levels without rebound, consistent with a small volume of distribution in a single-compartment model.