Juvenile nephronophthisis is a common cause of end stage renal failure in children and adolescents. The early occurrence with rapid progression to advanced renal failure has not previously been described. In this report we present three babies in whom failure to thrive, dehydration and a renal concentrating defect presented soon after birth; they were subsequently investigated for renal failure during the first year of life. In two cases the association with congenital hepatic fibrosis was noted. A family history of nephronophthisis was not present but the parents were consanguineous and one sibling had died in infancy.