Although bupivacaine remains a standard local anesthetic for postoperative epidural infusions in pediatric patients, it is increasingly being replaced with ropivacaine by many anesthesiologists. Ropivacaine is associated with less risk for cardiac and central nervous system toxicity. The purpose of this study was to compare analgesic efficacy and adverse events of postoperative epidural analgesia with ropivacaine/fentanyl versus bupivacaine/fentanyl in children after the Ravitch procedure and thoracotomy. This was a prospective randomized controlled study. This study was conducted at the Department of Thoracic Surgery of the Institute of Tuberculosis and Lung Diseases in Rabka Zdroj, Poland. 94 patients undergoing elective thoracic surgery. Patients aged 7-17 years were randomly allocated into a ropivacaine 0.2% (RF, n = 45) or bupivacaine 0.125% (BF, n = 45) group; 1 mL of each analgesic solution contained 5 μg fentanyl. All patients received acetaminophen and nonsteroidal anti-inflammatory drugs. Nurses assessed pain intensity and incidence of adverse events over 72 hours after surgery and modified analgesia if patient pain intensity was greater than 2 out of 10. There was no statistically significant difference in median pain scores and incidence of adverse events between the RF group and the BF group. The analgesia was excellent (median pain intensity scores at rest, during deep breathing, and when coughing was less than 1 out of 10 in all patients). Adverse events included incidents of desaturation (64/90), nausea (18/90), vomiting (31/90), pruritus (12/90), urinary retention (2/90), paresthesia (11/90), anisocoria (2/90), and Horner syndrome (2/90). Thoracic epidural analgesia using an RF and BF solution resulted in similar pain relief and adverse event profiles. •Thoracic epidural analgesia using a ropivacaine 0.2% combined with 5.0 μg/ml fentanyl and 0.125% bupivacaine with 5.0 μg/ml fentanyl resulted in similar pain relief and adverse event profiles.•Any adverse events are minor and easily reversible.•The modification of postoperative epidural analgesia by a nurse based on pain assessment and early identification and proper management of adverse events are a key to effective and safe epidural analgesia.