OBJECTIVE: The goals of this study were to describe the clinical and anatomic features of infants undergoing Kasai portoenterostomy (KPE) for biliary atresia (BA) and to examine associations between these parameters and outcomes. METHODS: Infants enrolled in the prospective Childhood Liver Disease Research and Education Network, who underwent KPE were studied. Patients enrolled in a blinded, interventional trial were excluded from survival analysis. Primary endpoints were successful surgical drainage (total bilirubin less than 2 mg/dL within the first 3 months), transplant-free survival (Kaplan-Meier), and time to transplant/death (Cox regression). RESULTS: KPE was performed in 244 infants (54% female; mean age: 65 +/- 29 days). Transplant-free survival was 53.7% and 46.7% at 1 and 2 years post-KPE. The risk of transplant/death was significantly lower in the 45.6% of patients who achieved successful bile drainage within 3 months post-KPE (HR: 0.08, P < 0.001). The risk of transplant/death was increased in patients with porta hepatis atresia (Ohi type II and III vs type I; HR: 2.03, P = 0.030), nonpatent common bile duct (Ohi subtype: b, c, and d vs a; HR: 4.31, P = 0.022), BA splenic malformation syndrome (HR: 1.92, P = 0.025), ascites > 20 mL (HR: = 1.90, P = 0.0230), nodular liver appearance compared to firm (HR: = 1.61, P = 0.008), and age at KPE >/= 75 days (HR: 1.73, P < 0.002). Outcome was not associated with gestational age, gender, race, ethnicity, or extent of porta hepatis dissection. CONCLUSION: Anatomic pattern of BA, BASM, presence of ascites and nodular liver appearance at KPE, and early postoperative jaundice clearance are significant predictors of transplant-free survival.