Iothalamate meglumine 17.2% was compared to saline as a testing medium in 72 consecutive infants and children undergoing lower urinary tract urodynamic assessment. A total of 97 studies was performed of which 85 were complete. Multiple urodynamic parameters were used to compare test results. Agreement in test results was noted when assessing the change in detrusor pressure in 68 studies (77.6%), leak or peak bladder pressure in 79 (92.9%) and bladder contractions on filling in 81 (95.3%). The difference noted between the 2 testing mediums when comparing these 3 parameters was not statistically significant. The cystometric bladder capacity did vary between iothalamate meglumine 17.2% and saline but no particular trend was identified. The difference in cystometric capacity calculated as a percentage change from the saline baseline was not statistically significant (p = 0.55). Iothalamate meglumine 17.2% can be used as a reliable testing medium for pediatric cystometry.