Since 1960s, immunosuppressive agents had critical role to prevent acute and chronic graft rejection and enhance graft survival in organ transplantation. With the dramatic advancement in immunosuppressive drugs, the average duration of graft survival has increased. Behind classical combination of those drugs, a lot of combinations with new drugs which has immunosuppressive property was proposed. This trend is continuing. Furthermore, numerous autoimmune and anticancer drugs with immunosuppressive properties are on repurposing for organ transplantation. This thesis provides an overview of the pharmacological property of organ transplantation related drugs. For the classic and novel type clinically applicable agents, mechanism of action and clinical efficacy are discussed. Subsequently, this thesis reviews agents currently under investigation that may have future potential.