The advantages and disadvantages of using corticosteroids in children undergoing cardiac surgery is still contentious. To examine how perioperative corticosteroids affect postoperative mortality and clinical outcomes in pediatric cardiac surgery with cardiopulmonary bypass (CPB). We used MEDLINE, EMBASE, and the Cochrane Database to conduct a comprehensive search up through January 2023. Children aged 0–18 undergoing cardiac surgery were included in the meta-analysis of randomized controlled studies comparing perioperative corticosteroids with other therapeutic therapies, placebo, or no treatment. All-cause hospital mortality was the primary endpoint of the study. Hospitalization duration was a secondary result. The Cochrane Risk of Bias Assessment Tool was used to evaluate the research quality. Ten trials and 7798 pediatric participants were included in our analysis. Children taking corticosteroids had no significant difference in all-cause in-hospital mortality using a random-effect model with relative risk (RR) = 0.38, 95% confidence interval (CI) = 0.16–0.91, I² = 79%, p = .03 for methylprednisolone and RR = 0.29, 95% CI = 0.09–0.97, I² = 80%, p = .04. For the secondary outcome, there was a significant difference between the corticosteroid and placebo groups, with pooled standard mean difference (SMD) = −0.86, 95% CI = −1.57 to −0.15, I² = 85%, p = .02 for methylprednisolone and SMD = −0.97, 95% CI −1.90 to −0.04, I² = 83%, p = .04 for dexamethasone. Perioperative corticosteroids may not improve mortality, but they reduce hospital stay compared to placebo. Further evidence from randomized controlled studies with larger samples is required for approaching at a valid conclusion.