Adequate pain management is crucial for pediatric patients undergoing open cardiac surgery. The aim of the present study was to investigate the effect of a bilateral transversus thoracis muscle plane (TTP) block on open cardiac surgery outcomes. First Affiliated Hospital of Nanchang University. Patients ages 6 to 60 months undergoing cardiac surgical procedures were included. A group of 100 children were randomly allocated to receive either bilateral TTP block (TTP group) or no nerve block. The primary endpoint was postoperative pain, which was measured with the Modified Objective Pain Score. The secondary outcome measures included intraoperative and postoperative fentanyl consumption; time to extubation; time to first feces; length of stay in the intensive care unit; length of hospital stay; and possible complications such as ropivacaine allergy, pneumothorax, hematomas, infections, and injuries to the internal mammary artery and vein. The TTP group had a significantly lower Modified Objective Pain Score until 24 hours after extubation than the no nerve block group. The TTP group reported significantly less fentanyl consumption. Time to extubation and lengths of stay in the intensive care unit and hospital were significantly decreased in the TTP group. Bilateral TTP blocks provide effective analgesia and accelerate recovery in pediatric patients. Copyright © 2020 Elsevier Inc. All rights reserved.