Autosomal recessive polycystic kidney disease is a heritable but phenotypically variable disorder characterized by varying degrees of nonobstructive renal collecting duct ectasia, hepatic biliary duct ectasia and malformation, and fibrosis of both liver and kidneys. In the kidney, the dilated collecting ducts and interstitial fibrosis, when severe, may significantly impair renal function and result in hypertension and renal failure. Imaging typically shows large but reniform kidneys, diffusely increased renal parenchymal echogenicity at ultrasonography, and a striated nephrogram after contrast material administration. In the liver, periportal fibrosis accompanies the malformed and dilated bile ducts; this may result in portal hypertension. The liver may appear normal or may show intrahepatic biliary dilatation; once portal hypertension develops, splenomegaly and varices are usually evident. The relative degrees of kidney and liver involvement tend to be inverse: Children with severe renal disease usually have milder hepatic disease, and those with severe hepatic disease tend to evidence mild renal impairment. Presently, treatment consists of supportive management and control of hypertension. Replacement therapy for renal failure (dialysis or kidney transplantation) and control of portal hypertension (portal circulatory diversion or liver transplantation) may be necessary.