The significance of extravasation of dye during excretion urography in blunt renal injuries has been controversial, with some believing that extravasation, even if copious, is largely innocuous and characterized by spontaneous resolution, and others believing extravasation is an indication for surgical correction of the underlying blunt renal injury. Thirty-two patients with extravasation diagnosed on excretion urography after blunt external trauma were evaluated. Immediate surgical management of the renal injury was performed in 18 patients who had a contusion in 1, laceration in 13, rupture in 3, and pedicle injury in 1, and averaged 2.0 associated injuries per patient. Conservative management of the renal injury was performed in 14 patients who averaged 1.1 associated injuries per patient. Ten of the 14 patients had a large renal laceration splitting the kidney or disrupting a pole with extravasation and none settled to normal. The data showed that extravasation with a small laceration resolved spontaneously while extravasation with a major disruption of the kidney did not settle to normal.