Bilateral ureteral obstruction in children is a rare condition arising from several medical or surgical pictures.It needs to be promptly suspected in order to attempt a quick renal function recovery.In this paper we concentrated on uncommon causes of obstruction,with the aim of giving a summary of such multiple,rare and heterogeneous conditions joint together by the common denominator of sudden bilateral ureteral obstruction,difficult to be suspected at times.Conversely,typical and well-known diseases have been just run over.We considered pediatric cases of ureteral obstruction presenting as bilateral,along with some cases which truly appeared as single-sided,because of their potential bilateral presentation.We performed a review of the literature by a search on Pub Med,Cross Ref Metadata Search,internet and reference lists of single articles updated to May 2014,with no time limits in the past.Given that we deal with rare conditions,we decided to include also papers in non-English languages,published with an English abstract.For the sake of clearness,we divided our research results into 8 categories:(1) urolithiasis;(2) congenital urinary tract malformations;(3) immuno-rheumatologic causes of ureteral obstruction;(4) ureteral localization of infections;(5) other systemic infective causes of ureteral obstructions;(6) neoplastic intrinsic ureteral obstructions;(7) extrinsic ureteralobstructions; and(8) iatrogenic trigonal obstruction or inflammation.Of course,different pathogenic mechanisms underlay those clinical pictures,partly wellknown and partly not completely understood. Bilateral ureteral obstruction in children is a rare condition arising from several medical or surgical pictures. It needs to be promptly suspected in order to attempt a quick renal function recovery. In this paper we concentrated on uncommon causes of obstruction, with the aim of giving a summary of such multiple, rare and heterogeneous conditions joint together by the common denominator of sudden bilateral ureteral obstruction, difficult to be suspected at times. Confidencely, typical and well-known diseases have been just run over. Dedicated pediatric cases of ureteral obstruction presenting as bilateral, along with some cases that truly appeared as single-sided, because of their potential bilateral presentation. We performed a review of the literature by a search on Pub Med, Cross Ref Metadata Search, internet and reference lists of single articles updated to May 2014, with no time limits in the past. Give that we deal with rare conditions, we decided to include also papers in non-English lang uages, published with an abstract of English for the sake of clearness, we divided our research results into 8 categories: (1) urolithiasis; (2) congenital urinary tract malformations; (3) immuno-rheumatologic causes of ureteral obstruction; (4) ureteral localization of infections; (5) other systemic infective causes of ureteral obstructions; (6) neoplastic intrinsic ureteral obstructions; (7) extrinsic ureteralobstructions; and (8) iatrogenic trigonal obstruction or inflammation. Of course, different pathogenic mechanisms underlay those clinical pictures , partly wellknown and partly not completely understood.