The kidneys are a pair of bean-shaped organs that are located in the retro-peritoneal space of the abdominal cavity. The retro-peritoneal space is the area located behind the peritoneum, a membrane that lines the abdominal cavity. The kidneys are located on either side of the spine, protected by the lower ribs and surrounded by a layer of fat that helps cushion them from injury. Being located in the retro-peritoneal space also allows for the kidneys to have easy access to the blood supply and urinary tract.