The immunosuppressant mycophenolate mofetil (MMF; CellCept) has greatly improved transplant recipients' clinical outcomes, but its efficacy may be limited by dose adjustments due to adverse events (AEs). An enteric-coated formulation of mycophenolate sodium (EC-MPS; myfortic), designed to improve gastrointestinal tolerability is now available. This Latin-American, prospective, multicenter, open-label, 6-month trial assessed the safety and tolerability of converting renal transplant recipients from MMF to EC-MPS. In total, 237 renal transplant recipients (stable > or = 3 months' posttransplant) receiving MMF (< or =1000 mg b.i.d.) were enrolled. Adults (n = 218) were converted to EC-MPS 720 mg b.i.d. (equimolar to MMF 1000 mg b.i.d.) even if they were initially receiving <1000 mg MMF b.i.d. (ie, 47 adults received a higher than equimolar dose of EC-MPS). Children (n = 19) were converted to EC-MPS 450 or 432 mg/m2 b.i.d. Patients also received cyclosporine microemulsion (Neoral) and corticosteroids. There were three acute rejections and no graft failures. The incidence of AEs was 59.9% (in those receiving a higher than equimolar EC-MPS dose it was 57.4%). In all, 22% of patients had gastrointestinal AEs, 37% had infections, and 4.8% had hematological AEs. Only 24 patients (10%) had an AE-related dose reduction. Seven of these patients had received higher than equimolar doses of EC-MPS. Patients can be safely converted from different doses of MMF to a standard dose of EC-MPS. The requirement for EC-MPS dose reduction to manage AEs was relatively low. Use of EC-MPS is a valid alternative for renal transplant recipients receiving maintenance MMF treatment.