A Randomized Study to Assess the Safety and Efficacy of Prograf vs Prograf-XL in de Novo Liver Transplant Recipients.

Inclusion Criteria: * Patient has been fully informed and has signed an IRB approved informed consent form and is willing and able to follow study procedures * Patient is a primary liver transplant recipient * Patient must receive first dose of XL or Prograf (or IV tacrolimus for subjects unable to tolerate oral study drug) within 48 hours of transplantation * Female patients of child bearing potential must have a negative urine or serum pregnancy test within 7 days prior to transplant Exclusion Criteria: * Patient has previously received or is receiving an organ transplant other than a liver * Recipient or donor is known to be seropositive for human immunodeficiency virus (HIV) * Patient has received a liver transplant from a non-heart beating donor * Patient has received an ABO incompatible donor liver * Patient has a current malignancy or a history of malignancy (within the past 5 years), except hepatocellular carcinoma within UCSF Criteria 21 and basal or non-metastatic squamous cell carcinoma of skin that has been treated successfully * Patient has fulminant hepatic failure, unless hemodynamically stable * Patient has an uncontrolled concomitant infection, a systemic infection requiring treatment (except viral hepatitis), or any other unstable medical condition that could interfere with the study objectives * Patient has severe diarrhea, vomiting, active peptic ulcer or gastrointestinal disorder that may affect the absorption of tacrolimus * Patient is currently taking or has been taking an investigational drug in the 30 days prior to transplant * Patient has a known hypersensitivity to tacrolimus, mycophenolate mofetil or corticosteroids * Patient is pregnant or lactating * Patient is unlikely to comply with the visits scheduled in the protocol, including the protocol biopsies * Patient has any form of substance abuse, psychiatric disorder or a condition that, in the opinion of the investigator, may invalidate communication with the investigator