Neonatal cholestasis is a pathologic state of reduced bile formation or flow, where contents normally excreted into bile are retained and measurable in blood. The incidence is approximately one in 2,500 live births. It is a typical presenting feature of neonatal liver disease rather than a late manifestation. Mechanisms are hepatocellular (viral hepatitis, Dubin-Johnson syndrome) or obstructive (choledochal cyst, biliary atresia). There is an extensive differential diagnosis, including neonatal sclerosing cholangitis, cystic fibrosis, hypothyroidism, and tyrosinemia. When pathologic jaundice is noted, a workup should begin promptly and include: