Purpose : Renal duplication is a common occurrence, and the range of ureteral and renal anomalies draining the two poles of the duplex kidney leads to a variety of clinical presentations. Method : A series of 61 children with duplicated systems was studied retrospectively who were admitted during last 12 years. Results : Of the children 60.6% were accompanied with urologic anomalies that required surgical treatment, and most children initially were presented with urinary tract infection. 42.6% of children were either diagnosed incidentally during evaluation of other non-urologic disease or during follow-up evaluation of abnormal antenatal renal sonogram. Conclusion : From our point view, children with history of abnormal antenatal renal sonogram, or with symptoms such as urinary tract infection, hematuria, abdominal pain should be evaluated radiologially fully to confirm further abnormality and accompanied complications. And routine follow-up using abdominal ultrasonogram, VCUG, and urine culture should be used to prevent and detect early treatable complications.