A consecutive series of 314 intravenous urograms performed in infants were reviewed and assessed for quality. The first 106 examinations were performed using sodium diatrizoate (Hypaque 270) as the contrast medium, the next 98 patients received metrizamide (Amipaque 280) and the final 110 received iohexol (Omnipaque 300). Thirty-five patients had to be excluded from the study for a variety of reasons, after which there were totals of 98 in the diatrizoate, 90 in the metrizamide and 91 in the iohexol groups. Assessing quality in terms of nephrographic and pyelographic density, sodium diatrizoate was found to be better than the non-ionic agents. Although the differences reached statistical significance they are small and unlikely to affect the information obtained in clinical practice. There was no difference in overall quality between metrizamide and iohexol. Comparing the degree of pyelographic distension and ureteric visualization using the three agents, no difference was found between the groups.