The purpose of the present study was to evaluate the possibility of application of pediatric hemodialysis system to dogs weighing less than 6 kg. Six healthy dogs (B .W, 3-6 kg) were used_ Experimental end-stage renal failure was induced by bilateral nephrectomy or bilateral ligation of ure-ters. Hemodialysis was performed when blood urea nitrogen (BUN) value increased over 90 mg/dl and every other day thereafter. Daily investigated parameters included clinical clinical signs such as vomiting, fecal appearance and activity and laboratory data such as PCV, WBC, RBC, BUN, creatinine, Ca, P, $Na^+ Cl^-and K^+$During hemodialysis treatment, BUN and creatinine values were measured hourly. Severe vomiting and inappetence were shown 2 days after infliction of kidney disorder and melena and mucous faces were observed 3 days. The signs were not corrected by hemodialysis treatment. Avel- age hemodialysis treatment time was <TEX>$5.5 { imes} 0.7$,/TEX> hours until BUN value decreased to normal range. Abnor- mal hematological and electrolytes values were reduced within normal levels after hemodialysis treatments. The complications oft hemodialysis included vomiting, nausea, obstruction of intravascular catheter, tremor, seizure, temporary visual loss and continued decrease in PCV It is suggested that pediatric hemedialysis system can be applied to acute renal failure and acute toxicity. Further works on improvements in maintaining patency of catheter and in managing the complications of hemo- dialysis should be conducted.