This study assessed the long-term effects of prolonged-release tacrolimus (Advagraf(®) [Tacrolimus QD]), which has been developed to provide similar efficacy and safety to twice-daily tacrolimus (Prograf(®) [Tacrolimus BID]) with the added benefit of once-daily dosing. Adult participants from four phase II de novo (kidney, liver) or Tacrolimus BID to QD conversion (kidney, heart) studies were enrolled into the follow-up study. Patients remained on the immunosuppressive regimen they were receiving on entry, unless medical needs required otherwise. The primary endpoint was patient and graft survival, and secondary endpoints were biopsy-confirmed acute rejection (BPAR) and safety. The full analysis set comprised 240 patients. Tacrolimus mean total daily dose and whole-blood trough levels decreased over time, particularly in de novo patients. At four yr, Kaplan-Meier estimates of patient and graft survival were over 90%. Freedom from BPAR was 90.9/92.6% and 100/87.0% in the de novo kidney/liver and conversion kidney/heart patients, respectively. There were 13 deaths, and 20% patients withdrew from the study, mainly because of adverse events. The efficacy and safety of Tacrolimus QD was maintained for four yr in kidney, liver, and heart transplant recipients. Therefore, this formulation offers a convenient alternative to Tacrolimus BID.