Congenital nephrotic syndrome (CNS) is an uncommon disorder. Several different diseases may cause the syndrome. These may be inherited, sporadic, acquired or part of a general malformation syndrome. The problems associated with nephrotic syndrome in early infancy are divided into three parts: diagnosis, treatment and prenatal diagnosis. Accurate diagnosis is essential for the treatment, genetic counselling and prenatal diagnosis. The ultimate curative treatment of CNS is renal transplantation. The supportive treatment before the transplantation is of utmost importance in order to maintain a reasonable clinical condition and prepare the child for the dialysis and renal transplantation. Prenatal diagnosis is possible in some types of CNS by determination of the maternal serum and amniotic fluid alpha-fetoprotein (AFP). Increased AFP indicates fetal proteinuria, and thereby nephrotic syndrome before birth. In some cases with the onset of proteinuria after birth prenatal AFP measurement does not detect the disease.