"Obstructive uropathy" is a generic term which combines different diseases in infants and childhood. Both the upper and lower urinary tract may be affected. Diseases of the urinary tract can cause an intrinsic obstruction. Sometimes tumours may cause a compression and as secondary effect an obstruction (extrinsic). Ultrasound is the key diagnostic tool and shows dilatation of the obstructed urinary tract. But for the functional exploration of babies and toddlers, renal scanning and X-ray examinations are necessary. These examinations lead to an exposure to radiation which necessitates careful indication. Some of the congenital diseases (for example ureteropelvic junction obstruction, megaureter) show a maturation without any intervention. So one has to decide whether to wait and see or to operate. A percutaneous nephrostomy or a DJ-catheter is not often used in the treatment of obstruction in general. These forms of drainage are more often used in the treatment of stones or of extrinsic obstruction. A pyelocutaneostomy or ureterocutaneostomy is a special surgical procedure in pediatric urology for transient drainage of the upper urinary tract (megaureter). The operation of a seriously ill new-born should be done in a centre for pediatric urology and pediatric nephrology. When the upper urinary tract is dilated, patients may need an antibiotic prophylaxis, because the dilatation of the upper urinary tract increases the risk of urinary tract infections (UTI). The indication for antibiotic prophylaxis should by guided by the criteria of the APN-Consensus Paper. Long-term follow-up is necessary and should comprise ultrasound, physical examination, controlling the blood pressure, urine analysis and blood tests. The aims of diagnostics, treatment and long-term follow-up are the preservation of renal function and to protect the children from UTI. This goal must be reached under conditions that are appropriate for children and their parents.