AbstractVarious animal models are used for research; however, non-human primates are well suited for biomedical research owing to their genetic homology with humans. The objective of this research was the anatomical characterization of red howler's kidneys in view of the scarcity of information in the literature. Protocols were approved by the Committee for Ethics in the Use of Animals at the Federal Rural University of Rio de Janeiro (number 018/2017). The study was conducted at the Laboratory of Teaching and Research in Domestic and Wild Animal Morphology, Federal Rural University of Rio de Janeiro. Specimens ofAlouatta guariba clamitanswere collected from the Serra dos Órgãos National Park road in Rio de Janeiro and subsequently frozen. Four adult cadavers (two males and two females) were used, identified, and injected with a 10% formaldehyde solution. Later, the specimens were dissected, and measurements and topography of the kidneys and renal vessels were recorded. The kidneys ofA. g. clamitansresemble a “bean seed,” with a smooth surface. The longitudinal section shows two distinct regions, cortical and medullary; in addition, the kidneys are unipyramidal. The renal arteries emerged from the abdominal aorta as a single vessel posterior to the renal veins. The renal veins drained directly into the caudal vena cava as a single vessel in all specimens.