Renal cortical and medullary infarction are 2 of the severe complications of perinatal asphyxia and shock. The angiographic and ultrasonographic findings in these conditions have not been described previously. They demonstrate nephromegaly, a nonhomogeneous nephrogram, and internal echoes. Similar findings may be seen in renal vein thrombosis, hydronephrosis, and polycystic kidneys.