The accuracy of diagnosis of primary and secondary tumors of the ureter is probably the poorest for any urologic condition. While urinary-sedimentation examinations search for certain biochemical by-products and cytologic examinations of the urine aided particularly by abrasion specimen have been helpful in identifying the presence of cancer cells or their metabolic by-products, the diagnosis rests first and foremost on the roentgenographic demonstration of an obstructing or space-occupying lesion (1, 12, 14). Although retrograde ureterograms are readily capable of identifying intraluminal mass lesions or diffuse stricture-like obstructing lesions, our acceptance of an incompletely visualized ureter attributed to peristaltic activity no doubt accounts for the frequent lag of diagnosis of these lesions (1, 2). Papillary tumors of benign or malignant variety can be readily differentiated against nonopaque calculi, blood clots, or seedling metastases on the basis of characteristic dilatation of the ureter distal to the growth, easily demonstrated on retrograde ureterograms; considerable difficulty, however, has been encountered in the diagnosis and differential diagnosis of diffuse stricture-like obstructive lesions such as infiltrative carcinoma of the ureter, varicosities of the ureter, extension of a carcinoma into the ureter from the outside, nonspecific inflammatory ureteritis, periureteral fibrosis, ureteritis cystica, and endometriosis (2, 8, 10, 12, 13). The known propensity of certain lesions in this latter group to present with a hypervascular pattern suggests that some of these lesions could opportunely be diagnosed by arteriography. The feasibility of angiographic demonstration of ureteric lesions has been reported by Boijsen who demonstrated two carcinomas of the lower third of the ureter angiographically (4). While the reproducibility of a diagnostic vascular pattern seen with primary carcinoma of the ureter has been questioned, it appears that arteriography should be extremely useful to confirm the diagnosis of such lesions as endometriosis, hemangioma, hemangiosarcoma, and many hypervascular metastatic tumors extending or metastasizing to the ureter such as carcinoma of the bladder, cervix, tube, and ovary (3, 6, 9, 10–12, 14). The common feature of all of these lesions is the hypervascular pattern identifiable on arteriograms which can be used to differentiate such lesions from all other lesions involving the ureter in the same area and presenting a like appearance on ureterograms. Although our experience has been limited, the validity of this claim appears to be adequately supported by the case material thus far studied. Anatomy The ureter receives the blood supply of its abdominal segment from the renal artery or its dorsal or ventral branches. Occasionally, the capsular artery may likewise contribute to the vascular supply of the ureter.