The purpose of this study is to compare the efficacy and safety of Prograf extended release(XL) plus MMF with Prograf plus MMF and steroid withdrawal 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