Background A drug regimen including a calcineurin inhibitor (cyclosporine or tacrolimus) and prednisone has been the mainstay of maintenance immunosuppresion in our renal transplant recipients for more than 10 years. After the introduction of mycophenolate mofetil (MMF), a new, potent immunosuppressant that may reduce the incidence of late rejection in renal transplant recipients, the immunosuppressive protocol in some recipients was changed to an MMF-based regimen. We sought to ascertain whether the addition of MMF lead to greater susceptibility to infectious complications. Patients and methods Between May 1991 and November 2002, all renal transplant recipients who received a two-drug regimen initially for more than 6 months were changed to an MMF-based regimen. The study includes patients with functional grafts for more than 6 months thereafter. Differences in the incidence, etiology, and outcome of infections were compared during the non-MMF versus the MMF periods. Results Eighty patients of mean age of 38.6 years (range 13 to 69) included 43 men and 37 women. The mean daily MMF dose was 663 mg/patient (range 250 to 1500 mg). The mean follow-up time of non-MMF period and MMF periods were 3.4 and 2.1 years, respectively. The overall incidence of infections in the two periods was similar (0.2 infections/patient in the non-MMF period and 0.25 infections/patient in the MMF period, P = .57). No mortality was associated with these infectious complications. In conclusion, addition of MMF, a more potent immunosuppressive protocol, did not increase the incidence of infections in stable renal transplant recipients initially treated with a two-drug regimen.