Bacterial colonization is regarded as a causative factor for septic complications of caudal catheters in children. To determine whether tunneling caudal catheters reduces the bacterial colonization rate effectively, we evaluated 506 children being treated with tunneled or untunneled caudal or untunneled lumbar epidural catheters. Four-hundred-nine children completed the study. After aseptic removal, the catheters were cultured and sent for microbiological assessment. We found a bacterial colonization rate of 29% in untunneled caudal catheters, 11% in tunneled caudal catheters, and 9% in untunneled lumbar catheters. No severe infectious complications were reported. There was no correlation between catheter retention time and bacterial colonization except for the first 24 h, during which no bacterial colonization was detected. The overall colonization rate remained constant at approximately 13%. We found a positive correlation between bacterial colonization and redness at the catheter entry site. We conclude that tunneled caudal epidural catheters can be used in children for postoperative analgesia without an increased risk of epidural infection.