A case of neonatal renal oxalosis in a 7-day-old calf is described. Clinical biochemistry revealed increased blood urea nitrogen. Gross findings included thin renal medulla and dilated renal calyces containing numerous, small, pale yellow and granular calculi. Histologically, most cortical and medullary tubules were dilated with birefringent crystals, whereas the glomeruli appeared unaffected. The crystals were morphologically consistent with calcium oxalate by the Pizzolato technique. Diffuse interstitial fibrosis and focal accumulations of lymphocytes were also noted.