The development and implementation of an infusion protocol for Orthoclone OKT3 (Ortho Biotech, Inc., Raritan, NJ) is described in this article. OKT3 is a potent immunosuppressant drug used to lower the incidence of graft rejection in transplant patients. Nurses and physicians use the protocol described in this article to administer OKT3 to heart and lung transplant patients at our institution. Pharmacokinetics, along with the nursing care, associated with OKT3 administration are described in the protocol section. The benefits of protocol use are reported in the conclusion.