Introduction: Biliary atresia implies high risk of mortality ifnot diagnosed and treated early. We undertook this study toassess the prognostic factors affecting the outcome ofKasai surgery.Methods: A retrospective clinical study was conductedamong 58 patients from Hospital Sultanah Bahiyah AlorSetar. Data were analysed with logistic regression analysisusing SPSS. Factors studied included age during surgery,bile duct diameter at the porta hepatic, race of patient,preoperative total bilirubin level and cholangitis. Thesefactors were analysed to determine its significance as aprognostic factor affecting the outcome of Kasai surgery.Results: Older age group above 56 days of life, bile ductdiameter at porta hepatis measuring <50µm, pre-operativetotal bilirubin >10mg% and cholangitis were found to bepoor prognostic factors from univariate regression analysis.Variables having p value<0.025 were analysed using themultivariable regression analysis. Only age of patient anddiameter of bile duct at the porta hepatis were eligible forthis analysis. The final analysis showed that age 57 days oflife and above (adjusted odd's ratio (aOR) = 9.412, p value =0.042, 95% confidence interval (95%CI) = 1.079 to 82.104) andbile duct diameter <50µm (aOR = 13.812, p value = 0.016,95%CI = 1.616 to 118.042) were significant factors affectingthe outcome.Conclusion: In conclusion, age of patient 56 days of life andyounger and diameter of bile duct at porta hepatis ≥50µmgave a significantly better outcome after Kasai surgery.