The Pharmacokinetics of furosemide (5 mg/kg iv) was investigated in rabbits with folate (75 mg/kg, 150 mg/kg 300 mg/ug, iv) induced renal failure. The plasma concentration was increased and urinary excretion was decreased significantly compared with those of normal rabbits. ${alpha},;{eta};and;K_{12},;K_{21},;K_{10}$ were decreased, $t_{1/2}$ and AUC were increased significantly. Correlation of serum creatinine concentration and AUC, renal clearance have linear relationship respectively. In short, dosage regimen of furosemide is considered to be adjusted in the dose size and the dosing interval by degree of serum creatinine concentration.