Kidney transplant restores renal function in eligible patients with end-stage renal failure who require renal replacement therapy. There remains a significant disparity between the demand and supply of suitable kidneys for transplant. In recent years, pediatric donors have formed an important area for expansion of the donor pool. However, neonatal donation (< 28 days) remains an underutilized resource. We describe a case of en bloc kidney transplant from a 5-day-old donor after circulatory death into an adult recipient. One kidney thrombosed almost immediately, leaving a single 4.5-cm, poorly functioning kidney. Eighteen months after transplant, the recipient has shown good function with the estimated glomerular filtration rate continuing to improve. This case demonstrates that a single neonatal kidney can grow and adapt to provide adequate renal function in an adult. This experience suggests that a single kidney from a neonate can sustain renal function in adults, and every effort should be made to maximize their use in transplant.