We examined the effect of various levels of dietary protein on long term prognosis of Adriamycinnephropathy of S-D rat, fed with high protein (30%), intermediately low (10%), and strictly low (5%) protein diet for 15 weeks. 1) In rats fed with strictly low protein diets (5%), proteinuria and serum creatinine decreased and creatinine clearance and histological changes were relatively well preserved. But hypoproteinemia and weight loss were more marked and 2 rats died due to severe ascites and pleural effusion in cachexic state. 2) In rats fed with high protein diets (30%), general health condition and weight gain were relatively well preserved. But there were massive proteinuria, progressive increase in serum creatinine and progressive decrease in creatinine clearance. Focal glomerular sclerosis and severe tubulointerstitial change on histologic examination were marked. 3) With intermediately low protein diet (10%), renal function and pasma protein levels were relatively well preserved compared with high protein diet group. But weight gain did not increase normally. 4) We tentatively conclude that appropriately restricted dietary protein can prevent functional and histological renal damage. But too strict protein restriction aggravate nutitional state and general condition.