Introduction: For diagnosis of extrahepatic biliary atresia (EHBA), there is no single biochemical test or imaging procedure entirely satisfactory. Diagnostic schemas incorporate clinical, laboratory, radio-logical and histopathological features are needed.Aim: Is to assess the sensitivity and specificity of diagnostic tools of EHBA including the changes in color of urine and stools, ultrasono-graphic findings suggestive of EHBA and liver biopsy.Materials and Methods: A retrospective study of 94 cholestatic infants that were diagnosed histopathologically as EHBA from 2005 to 2007 in Hepatology Unit of Pediatric Hospital, Cairo University. Of them, 50 patients were operated. There was two diagnostic groups: group І included 48 patients that were operated and proved to have EHBA and group П included 5 patients in which EHBA was excluded (2 patients were operated and 3 patients developed spontaneous remission). Statistical analyses were performed to evaluate sensitivity and specificity of diagnostic tools of EHBA.Results: The mean age of onset of symptoms in group І was 17.4 ± 21.4 days while the mean age of presentation was 60.6 ± 13.8 days. The sensitivity of clay colored stool was 79.06 % and the specificity was 50% while the sensitivity of dark urine was 61.9% and the specificity was 50%. Changes in total & direct bilirubin, ALT, AST, ALP and GGT would not be an accurate method to differentiate EHBA from other causes of cholestasis. The sensitivity of absent visualization or small size of gall bladder was 85.4% and the specificity was 25% while the sensitivity of TC sign was 31.3% and the specificity could not be calculated. Liver biopsy had an overall accuracy of 90.7% (48/53 patients). Bile plugs had a sensitivity of 66.7% and specificity of 80.0%. Oedema and infiltration with inflammatory cells had equal sensitivity of 89.6% while the specificity for both can not be calculated. Conclusion: Percutaneous liver biopsy is widely regarded as the most valuable study for evaluating neonatal cholestasis. Ultrasonographic evaluation may have a greater value in the future if new findings (such as the triangular cord sign) are confirmed. Scintigraphy, MRCP and ERCP are not routinely recommended but may be useful in doubtful cases. (It remains for the present that if the biopsy is suggestive of obstruction, most physicians then proceed with an intraoperative cholangiogram).