Belgrade rats carry a disabling mutation in the iron transporter DMT1. Although DMT1 plays a major role in intestinal iron absorption, the transporter is also highly expressed in kidney, where its function remains unknown. The goal of this study was to characterize renal physiology of Belgrade rats. Male Belgrade rats died prematurely with ~50% survival at 20 weeks of age. Necropsy results indicated marked glomerular nephritis and chronic end-stage renal disease. By 15 weeks of age, Belgrade rats displayed altered renal morphology associated with sclerosis and fibrosis. Creatinine clearance was significantly lower compared with heterozygote littermates. Urinary biomarkers of kidney injury, including albumin, fibrinogen and Kim-1, were significantly elevated. Pilot morphological studies suggest that nephrogenesis is delayed in Belgrade rat pups due to their low iron status and fetal growth restriction. Such defects in renal development most likely underlie the compromised renal metabolism observed in adult b/b rats. Belgrade rat kidney non-heme iron levels were not different from controls but urinary iron and transferrin levels were higher. These results further implicate an important role for the transporter in kidney function not only in iron re-absorption but also in glomerular filtration of the serum protein.