The angiographic patterns of renal carcinoma were extensively studied and described by Boijsen and Folin (1) in 1961. Numerous additional reports have accumulated in the literature in the differential considerations of benign and malignant tumors, but nowhere have we been able to find a report on the angiographic patterns of Wilms's tumor. This is probably accounted for by the great rarity of this tumor in the adult and, furthermore, by the fact that renal angiography is infrequently performed in evaluating the kidneytumors of children. We have had the recent opportunity of utilizing angiographic technics in the evaluation of Wilms's tumor in both a child and an adult. The relative similarity of the angiographic patterns in these two instances would tend to indicate that there may be a peculiarity in the vascular changes associated with Wilms'stumor justifying a report on this limited number of patients. Case I: A 4-year-old male was admitted to the hospital with a twenty-four-hour history of left lower q...