Inclusion Criteria:

• Men and women 18-65 years of age who are recipients of a renal transplant at least 6 months prior to enrollment
• Patients on oral Prograf therapy as part of their maintenance immunosuppression therapy, with stable doses and trough levels of tacrolimus of 7-12 ng/mL for at least two weeks prior to enrollment.
• Patients maintained on concurrent immunosuppression with mycophenolate mofetil (MMF, CellCept) or mycophenolic acid delayed-release tablets (Myfortic), with stable doses for at least two weeks prior to enrollment
• Patients with serum creatinine < 2.0mg/dL prior to enrollment
• Able to swallow study medication
• Patients capable of understanding the purposes and risks of the study, who can give written informed consent and who are willing to participate in and comply with the study
• Women of childbearing potential must have a negative serum pregnancy test within seven days prior to receiving study medication
• Patients who successfully pass a drug screen

Exclusion Criteria:

• Recipients of any transplanted organ other than a kidney
• White blood cell count < 2.8 x 10^9 /L
• Patients who are receiving a total dose of Prograf for 24 hours < 3mg
• Patients unable or unwilling to provide informed consent
• Pregnant or nursing women
• Patients with reproductive potential who are unwilling/unable to use a double barrier method of contraception
• Administration of other investigational agent in the three months prior to enrollment
• Patient receiving any drug interfering with tacrolimus metabolism
• Patients who have taken sirolimus within the past three months prior to screening
• Patient with an episode of acute cellular requiring antibody therapy within the 6 months prior to enrollment
• Patient treated for acute cellular rejection within the 30 days prior to enrollment
• Patient who is HCV negative and has received an HCV positive (HCV RNA by PCR or HCV antibody) donor kidney
• Patient has a current malignancy or a history of malignancy (within the past 5 years), except basal or non-metastatic squamous cell carcinoma of the skin that has been treated successfully
• Patient has uncontrolled concomitant infection, a systemic infection requiring treatment, 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 will require therapy with any immunosuppressive agent other than those prescribed in the study
• Patient has a known hypersensitivity to corticosteroids, mycophenolate mofetil, mycophenolic acid or tacrolimus
• Patient has any form of current substance abuse, psychiatric disorder or a condition that, in the opinion of the Investigator, may invalidate communication with the Investigator