The elongated kidneys of Caiman crocodilus yacare are found in pairs and have two lobes. Each lobe is crossed lengthwise down the middle by the renal vein and artery along which there are the renal corpuscules in groups of two or four which delimit the medullar renal region. These corpuscules are generally poorly developed and there is a center of connective tissue with few capillary loops. The Bowman capsule is of pavement or cubic epithelium and leads into a narrow, short, non-secretory neck segment composed of cubical cells followed by tubulus contortus with brush borders against the lumen and the distal tubule with cubic epithelium brush borders. In the renal cortical region are the median tubulus with cylindrical and granular epithelium and the smaller collecting canals which flow into larger collecting canals which flow along the renal border. Among the various tubular parenchyma segments there is a network of blood vessels which lead into the renal vein and into a renal afferent vein. Abundant fat granular bodies and lipid droplets are observed in the proximal and median tubules. The collecting canals and ureters show PAS positive granules in their cells.