This paper reports the occurrence of renal disease in six young Japanese Black cattle. Their kidneys were atrophic and of granular appearance. Histologically, they exhibited interstitial fibrosis with inflammatory cell infiltration, clusters of atrophic and cystic tubules, and thickening of tubular and Bowman's basement membranes. Glomeruli were markedly reduced in numbers and were hypercellular due to mesangial proliferation. The affected cattle had a common male ancestor, suggesting a familial basis for this disease.