The application of antenatal ultrasound for the evaluation of congenital anomalies in early pregnancy has become a common practice. Hydronephrosis is the most common anomaly observed. Antenatal interventions are experimental and done in advanced centers. Though there are defined criteria of intervention, it is still not clear as to who will benefit. Most patients will have relatively benign course, however identification of those who will have potentially serious postnatal problems permits early intervention. This study gives recommendations for the postnatal examination and follow-up of the newborns having hydronephrosis diagnosed on antenatal ultrasound.