The retroperitoneal lumbar vessels should be immediately recognized during urological, vascular and radiological medical procedures. Few studies have tried to define an exact pattern for the lumbar vasculature and most of the anatomical descriptions suggest the presence of a regular pattern. Nevertheless, for the renal blood vessels, despite the described regular pattern, several anatomical variations have interested anatomists for more than a century. Taking into account that there is a constant need for reviewing this anatomy due to the advances in surgical and/or uroradiological procedures techniques, we describe a complex variation of the renal blood vessels found during the dissection routine in our laboratory. A male cadaver, aged 65 years, embalmed with 10% formalin solution presented, on the left side, two renal arteries arising from the abdominal aorta, both of them entering the kidney on the hilar region. From the hilar region of the left kidney, there were also two tributary renal veins, which join together 3.0 cm from the hilus, before draining into the inferior vena cava. These two tributary veins were large in diameter, and made a loop around the two renal arteries and also the ureter. No anatomical variations were found on the right side. This is a complex anatomical variation of the renal vessels which might have functional implications once the venous loop described might be a compression factor for the renal arteries and for the ureter.