Although almost all classifications of anomalies of the ureter include congenital ureteral valve, it is usually considered that it rarely, if ever, occurs as a primary obstructive lesion. W olffer1 first directed attention to their existence in 1887 with a report in which autopsy examination of 100 newborns revealed the presence of 20 ureters with'more or less definite cross folds'. Subsequent studies by Englisch, 2 Robinson, 3 and Gerard4 report lower occurrence and most authors accept 5 per cent as the likely incidence of ureteral valves in the newborn. These structures are vestigial remnants that disappear early in life and are considered by most investigators5• 6 as unlikely to be responsible for obstruction of the ureter. Reduplication of the ureteral mucosa with formation of kinks and valves is not infrequently seen in tortuous dilated ureters in which a primary obstructive factor exists lower in the urinary tract with secondary kinking and valve-like formation. Rolnick7 believed the case of Gottleib8 to be the only authentic case in which the valve was responsible for obstruction, although he states:" Unfortunately, no drawing of the specimen accompanies the report, so it is uncertain whether the valve was primary or secondary to a kinking of the ureter by a hydronephrosis." Since no previous survey of the literature has been reported, the following criteria are proposed in evaluation of cases to determine their authenticity as pri-mary lesions responsible for obstruction of the ureter: 1) anatomically demonstrable transverse folds of ureteral mucosa which contain bands of smooth muscle; 2) changes of obstructive uropathy above valve, with normal urinary tract below; 3) no other evidence of mechanical or functional obstruction. These criteria were used in analysis of reported cases. A total of 11 cases were reviewed, 4 of which were found to meet the above requirements (table 1). The case of Barclay and Baird9 was considered by the authors to be obstructive, but since no anatomical studies were made and obstruction existed at two different levels, it is impossible to differentiate from ureteral stricture, and is therefore not used. Vermooten10 (case 4) describes the surgical excision of bilateral congenital valves in a 16 month male, but unfortunately, no description of the lower urinary tract, other than mention of the fact that the bladder wall was moderately