Febrile infants undergoing urethral catheterization (UC) are often not treated for pain and distress. The aim was to evaluate the effectiveness of midazolam premedication. We compared a convenience sample of infants who underwent UC with midazolam with those who did not receive midazolam. Outcome measures were Visual Analog Scale assessment, duration of cry, and emergency department length of stay. Thirty-two study participants and 18 controls were prospectively enrolled. Midazolam premedication showed a 53% decrease in the mean Visual Analog Scale score when parents assessed distress (33.6 vs. 71.7, P<0.0001) and a 48% decrease when nurses assessed distress (28.7 vs. 55.5, P<0.0002); the median cry duration was significantly shorter (0 vs. 240 s). Serious adverse events were not observed during sedation and at 48 h after discharge. Study participants had longer emergency department length of stay compared with the controls (191.5 vs. 139 min, P<0.017). In this cohort, midazolam significantly reduced the distress associated with UC without causing serious adverse events.