The second generation of mammalian target of rapamycin (mTOR) inhibitor everolimus has been applied as an immunosuppressive drug in patients receiving kidney transplantation as well as heart transplantation from December 2011 in Japan. Therapeutic drug monitoring (TDM) is required to adjust dosage in use of everoilmus as well as cyclosporine and tacrolimus in organ transplant patients. Recently, The Japanese Society of Therapeutic Drug Monitoring (JSTDM) has developed and launched the fi rst TDM guideline to standardize the routine TDM practice for immunosuppressive drugs (ISD) used in kidney, liver and heart transplantations. Toward the establishment of individualized dosage regimen of everolimus in organ transplant patients, periodic revision of the guideline would be required. In the present review, the recent development of everolimus TDM in the transplant patients has been summarized referring the first Japanese TDM guideline of immunosuppressive drugs.