—Mackey1 stated that hemangiomas of the kidney are rare but significant because of the urgent necessity at times of surgical procedures for severe hemorrhage. In a case of his a diagnosis of renal tumor was made because of symptoms of renal colic, severe unilateral hemorrhage and the shadow of a filling defect in the pyelogram. An angioma of the lower major calix was found.Mackey reviewed from the literature 17 cases of renal angiomas which caused hemorrhage sufficiently severe to necessitate surgical treatment. The cases are classified according to their situations in order to determine whether they may be distinguished by any constant clinical feature. In 6 cases the wall of the renal pelvis was involved, and the suddenness and severity of the hemorrhage necessitated immediate intervention. In none of the 4 cases of angioma of the cortex or the pyramids did hemorrhage constitute a surgical emergency.