Renal involvement characterized by interstitial nephritis and glomerulonephritis is reported in a case of visceral leishmaniasis in a dog. Focal interstitial inflammatory infiltrates including lymphocytes and plasma cells together with collections of histiocytes containing Leishmania donovani organisms were found in the renal cortex. The glomeruli showed diffuse mesangial cell proliferation, thickening of the capillary wall and focal, segmental glomerulosclerosis. By electron microscopy, finely granular electron dense deposits were shown in subendothelial, intramembranous as well as subepithelial locations. It is suggested that the interstitial nephritis was caused by the presence of parasitic elements in the renal interstitium, whereas the glomerular involvement may have been due to deposition of antigen-antibody complexes.