Mycophenolate mofetil (MMF) is a new immunosuppressive agent with proven efficacy in the prevention of rejection in renal transplant recipients. Clinical studies in heart transplantation have suggested efficacy in patients with refractory and persistent rejection. A large multicenter randomized primary prevention trial in heart transplant patients has just been completed and suggests benefits of MMF in survival and treated rejection episodes. This drug appears to be well tolerated without significant increase in infection or other complications. MMF appears to be an important immunosuppressive agent in cardiac transplant recipients.