Aluminum (Al) contaminates total parenteral nutrition (TPN) solutions given to infants, and high levels of Al have been demonstrated in their bone, serum, and urine. However, it is uncertain whether Al at current levels of contamination of TPN solutions is harmful to bone. We report an 8-month-old infant who developed osteopenic bone disease while receiving TPN, which did not respond to large amounts of calcium, phosphate, and vitamin D2. Serum and urine Al levels were greatly elevated and fell after a short course of deferoxamine. However, shortly after treatment began, serum calcium levels fell in the absence of hypercalciuria. We postulate that chelation of Al from this patient's bone permitted increased bone calcium uptake. This would suggest that Al at current levels of contamination of TPN solutions may impair bone calcium uptake and thus contribute to the pathogenesis or exacerbation of TPN-related osteopenia.