Why is a transplanted kidney usually placed in the lower abdomen instead of its original location?

In a kidney transplant, the new organ is implanted in the iliac fossa—a space in the groin area—rather than its original location primarily to facilitate the surgical connection of blood vessels.

By placing the kidney in the lower abdomen, surgeons can more easily attach the renal artery and vein to the recipient's iliac artery and vein. Additionally, this location allows the ureter of the transplanted kidney to be connected directly to the bladder or the existing ureter. Surgeons typically place a right kidney in the left fossa and vice versa to further optimize the alignment for these vascular attachments.1

The recipient's original kidneys are generally left in place unless they are infected or physically too large to accommodate the new organ.1