As a result of the rapid increase in medical costs, the efficacy of diagnostic imaging is under examination, and efforts have been made to identify patients who may safely be spared radiographic imaging. We reviewed the records of children who presented to our institution with suspected blunt renal injuries to determine if radiographic evaluation is necessary in children with microscopic hematuria and blunt renal trauma. We retrospectively reviewed the medical records of 1200 children (ages less than 18 years) who sustained blunt abdominal trauma and who presented to our level I pediatric trauma center between 1995 and 1997. Urinalysis was performed in 299 patients (25%). Urinalysis results were correlated with findings on abdominal computed tomography (CT). All patients had more than three red blood cells per high power field (RBC/ hpf) or gross hematuria. Renal injuries were graded according to the injury scale defined by the American Association for the Surgery of Trauma. Sixty-five patients had microscopic hematuria. Thirty-five (54%) were evaluated with an abdominal CT scan. Three patients sustained significant renal injuries (grade II-V), and 32 patients had normal findings or renal contusions. Therefore only 3 of 65 patients (4.6%) sustained a significant renal injury. All three patients had other associated major organ injuries. Of the three patients with gross hematuria evaluated with abdominal CT, one (33%) sustained a significant renal injury and had no associated injuries. The degree of hematuria did not correlate with the grade of renal injury. Pediatric patients with blunt trauma, microscopic hematuria, and no associated injuries do not require radiologic evaluation, as significant renal injuries are unlikely. However, children who present with associated injuries and microscopic hematuria after blunt trauma may have significant renal injuries and should undergo radiologic evaluation.