For rats, glomerular filtration rate (GFR) and its relative GFR (ratio to normal GFR₀) were estimated in order to classify their chronic kidney disease (CKD) into 5 stages like those in humans. The adenine-loaded rats, which were used to show the intrinsic antioxidant and creatinine (Cr) metabolite, NZ-419 (5-hydroxy-1- methylimidazolidine-2,4-dione), when taken orally, prevented the progression of chronic renal failure (CRF), were used as a model to reach the severest stage 5. In this report, we show that, by using both a tubular lesion and a glomerular lesion models (adenine-loaded and 5/6 nephrectomized rats, respectively), peroral NZ-419 might be a common tool to prevent the progression of CRF at CKD stages 3 and 4 under the condition that most rats in the control group still remained at stage 4 (0.15<GFR/GFR₀<0.29) at the last. At the minimum effective dose (MED: 100 mg/kg/d) of NZ-419 in adenine-loaded rats, serum Cr and all oxidative stress markers were ameliorated. Two doses (80, 160 mg/kg/d), at around the MED, used for 5/6 nephrectomized rats with a similar CRF severity, gave significant inhibitory effects against the increases in blood urea nitrogen, decreases in renal blood flow and renal plasma flow, and nephrotic syndrome. Oxidative stress markers, the urinary methylguanidine and serum albumin level, were significantly ameliorated.