The Proceedings of the Fifth International Pediatric Nephrology Symposia are dedicated to those who make the writing possible: the delegates; those who wanted to attend, but could not, and to our colleagues, families and friends who helped organize the meeting. with the advent of certification of pediatric nephrologists in the USA and the increasing numbers of pediatric nephrologists contributing to and practic ing this specialty throughout the world, it is appropriate that we begin to record our international symposia in order to periodically document the State of the Art of pediatric nephrology and to share new information in a timely fashion with colleagues who care for children. Four previous international pediatric nephrology symposia have been spon sored by the International Pediatric Nephrology Association. These meetings were held in Guadalajara, Mexico, 1968, Paris, France, 1971, Washington, DC, USA, 1974 and Helsinki, Finalnd, 1977. This is the first time that it has been possible to organize the publication of the proceedings of a symposium. The enclosed manuscripts represent more than seventy percent of the symposia presentations delivered at the Fifth International Pediatric Symposia (October 6-10, 1980, Phila., PAl which was - hosted by St. Christopher's Hospital for Children and The Children's Hospital of Philadelphia representing the Departments of Pediatrics of Temple University School of Medicine and The University of Pennsylvania School of Medicine."