This will be a phase 4, 4 center, and randomized pilot study. Kidney, pancreas or combined kidney/pancreas transplant patients that receive induction anti-thymocyte globulin or OKT3 and/or are either seropositive for CMV or receive a graft from a CMV seropositive donor will receive Valcyte™ 900 mg daily for 90 days. Patients will then be randomized to either 450 mg or 900 mg Valcyte™ each day for days 91 to 365. Patients will be serially monitored for the development of ganciclovir-resistant CMV. Patients will receive standard immunosuppression, antibacterial and antifungal prophylaxis, and other necessary medications as determined by their physicians.