Hematuria after blunt abdominal trauma is common with multiple organ system injuries, and many trauma centers routinely perform intravenous pyelography (IVP) on all trauma patients having any degree of hematuria. However, it has been suggested that many IVPs could be avoided if more selective criteria were used. To help determine the need for an IVP, we reviewed the records of 102 consecutive patients undergoing IVP after blunt abdominal trauma over a 17-month period. Twenty-six (25%) patients had gross hematuria. Of these, seven (27%) had abnormal IVPs, and two (7.7%) of those required urologic surgery. Seventy-six (75%) patients had microscopic hematuria. Of these, one (1.3%) had an abnormal IVP but required no urologic surgery. Thus, if IVP had been performed only when gross hematuria was present, then all surgically significant urinary tract lesions would have been recognized, and 75 per cent of these 102 patients would have been spared IVPs. We agree with others that microscopic hematuria alone is not an indication for emergency IVP in these trauma patients. However, gross hematuria or other strong clinical evidence of renal injury still mandates IVP early during the assessment of patients who have suffered blunt abdominal trauma.