We evaluated prospectively 506 consecutive patients who presented with a history of blunt trauma and hematuria. All patients initially underwent excretory urography and cystography. Of the 506 patients 25 had detectable urinary tract injuries that were confirmed either by the initial studies or by computerized tomography, angiography or direct intraoperative inspection. Diagnoses included 7 renal contusions, 7 renal lacerations (1 major and 6 minor), 1 renal artery, 3 intraperitoneal and 5 extraperitoneal bladder ruptures, and 2 urethral injuries. Of the 25 patients 21 presented with gross hematuria, including all of those with lower tract injuries. One of the 4 patients who presented with microhematuria was hospitalized in shock. Of the remaining 3 patients with microhematuria and no shock 1 had a minor renal laceration and 2 had renal contusions. All 3 patients were managed conservatively and all 3 were hospitalized chiefly for associated nonurological injuries. If the patients who presented with microhematuria and no shock were excluded from initial radiographic evaluation, 1 minor renal laceration and 2 renal contusions would have been missed. If we had added 1 more exclusion criterion, that of absence of major associated injuries, we would not have missed an injury.