Male Wistar rats fed 2 per cent oxonic acid plus 3 per cent uric acid for 3 weeks developed hyperuricemia and an extraordinary uricosuria. The kidneys had gross abnormalities similar to those seen in humans with gouty nephropathy. The cortical surfaces were granular and the kidneys had uric acid and urate deposits in the intratubular and intestitial spaces of the medullary region. Both histologic and ultrastructural studies of the glomeruli failed to disclose any unusual morphologic changes. Glomerular cells were normal and glomerular basement membranes maintained the granular structure of the lamina densa with a clear demarcation between the lamina rara externa and lamina rara interna. These morphologic findings suggest that in acutely hyperuricemic rats with a lesion comparable to hyperuricemic tubular blockade, there is no associated glomerular alteration.