BACKGROUND: Adult patients with biliary acute pancreatitis (BAP) or choledocholithiasis who do not undergo cholecystectomy on index admission have worse outcomes. Given the paucity of data on the impact of cholecystectomy during index hospitalization in children, we examined readmission rates among pediatric patients with BAP or choledocholithiasis who underwent index cholecystectomy versus those who did not. METHODS: Retrospective study of children (< 18 years old) admitted with BAP, without infection or necrosis (ICD-10 K85.10), or choledocholithiasis (K80.3x-K80.7x) using the 2018 National Readmission Database (NRD). Exclusion criteria were necrotizing pancreatitis with or without infected necrosis and death during index admission. Multivariable logistic regression was performed to identify factors associated with 30-day readmission. RESULTS: In 2018, 1122 children were admitted for index BAP (n = 377, 33.6%) or choledocholithiasis (n = 745, 66.4%). Mean age at admission was 13 (SD 4.2) years; most patients were female (n = 792, 70.6%). Index cholecystectomy was performed in 663 (59.1%) of cases. Thirty-day readmission rate was 10.9% in patients who underwent cholecystectomy during that index admission and 48.8% in those who did not (p < 0.001). In multivariable analysis, patients who underwent index cholecystectomy had lower odds of 30-day readmission than those who did not (OR 0.16, 95% CI 0.11-0.24, p < 0.001). CONCLUSIONS: Index cholecystectomy was performed in only 59% of pediatric patients admitted with BAP or choledocholithiasis but was associated with 84% decreased odds of readmission within 30 days. Current guidelines should be updated to reflect these findings, and future studies should evaluate barriers to index cholecystectomy.