Objective: The aim of this study is to validate the efficacy and reliability of two predictive models for postoperative fever after retrograde intrarenal surgery (RIRS) in pediatric patients Materials and Methods: A total of 124 children who were treated with RIRS between August 2014 and August 2020 in our center were included. All the predictors were obtained by preoperative routine examinations. Receiver operative curve (ROC) and area under curve (AUC) were showed to compare the predictive power of the two models. Results: One hundred twenty-four children included of 94 boys and 30 girls, with median ages of 2.1 (1.3, 7.0) years and median body mass index of 17.3 (15.6, 20.6) kg/m(2). The total points of the two nomograms were 81.0 (67.3, 90.3) and 45.5 (20.4, 94.0). Eventually, 21 children (16.9%) suffered from postoperative fever. With the exception of C-reactive protein values (25.0 mg/L vs 5.0 mg/L, p = 0.015), irrigation volumes (800 mL vs 500 mL, p = 0.01), and total points of the two predictive models (Nomogram 1: 88.0 vs 76.0, p < 0.001; Nomogram 2: 76.0 vs 39.0, p = 0.016), there was no statistical difference detected between the fever and nonfever groups. ROCs showed that Nomogram 1 presented with better predictive accuracy and efficacy with excellent AUC values of 0.805 in comparison with Nomogram 2 (0.805 vs 0.664, p = 0.025). Conclusion: We reported a sample of 124 children undergoing RIRS with a final stone-free rate of 87.1%. Twenty-one pediatric patients (16.9%) suffered from postoperative fever. Nomogram 1 presented with better predictive power for postoperative fever after RIRS in pediatric patients.