The results of investigations in children with urinary tract infection (UTI) were studied in a district general hospital in order to assess the relative value of the two most widely used screening tests, namely ultrasound (US) and 99mTc dimercaptosuccinic acid (DMSA) scintigraphy. A total of 193 children had undergone both US and DMSA scintigraphy as part of an investigation of proven single or multiple urinary tract infections over a 27 month period. DMSA scintigraphy revealed abnormalities in 22 of the children (11%). The abnormalities ranged from cortical defects to congenital anatomical abnormalities. US revealed abnormalities in six children (3%) but did not contribute any additional information in any. In our institution, the DMSA scintigram alone would have been an adequate screening test for children with UTI. Hydronephrosis is a common abnormality detected by US. Although none were seen in the study group, several children were examined during the study period with dilated collecting systems detected at ante-natal US. No cases of hydronephrosis presented as UTI. We question whether the use of routine US is justifiable in the investigation of children with UTI, and discuss whether a more selective investigation protocol should be adopted.