INTRODUCTION: Biliary atresia (BA) is the leading cause of childhood liver failure requiring liver transplantation. Early diagnosis and Kasai portoenterostomy (KP) offer the only opportunity to avoid liver failure and transplantation. This study aimed to assess BA healthcare costs in the United States. We hypothesized that patients who underwent KP before 60 days of age would incur lower healthcare costs than patients who underwent KP at 60 days or older. METHODS: Using MarketScan® (Truven Health Analytics), we evaluated cumulative healthcare costs for BA patients who had KP at less than 60 days (early KP), at 60 days or older (late KP), or had liver transplant - primarily or following KP. Cumulative costs were calculated at one-, three-, and five-year intervals, stratified by age at KP and transplant status. ANOVA univariate and Gaussian multivariate analyses were performed. RESULTS: 170 children with BA were identified: 86 underwent early KP (50.6 %), 78 underwent late KP (45.9 %), and six were primarily transplanted (3.5 %). 101 patients (59.4 %) were enrolled in their insurance plan at one year, 45 (26.4 %) at three years, and 23 (13.5 %) at five years. Predicted total costs at three years were 83,035 for early KP (no transplant), 38,958 for late KP (no transplant), and ,015,806 for patients requiring transplant regardless of KP status. CONCLUSION: The average healthcare costs for BA patients are significant and depend upon age at intervention. Nearly 90 % of children experience insurance discontinuity within five years of diagnosis. Early BA diagnosis is integral to optimizing outcomes and minimizing healthcare expenditures. TYPE OF STUDY: Retrospective cohort study.