Inclusion Criteria:  Patients who at least 1 year and less than 10 years after kidney transplantation Over 20 years old Patients on immunosuppressive maintenance therapy using combination of Calcineurin Inhibitor and Mycophenolic acid after kidney transplantation  Exclusion Criteria:  Patients who have transplanted organs other than kidney  At the time of Screening  Treatment with active liver disease or Liver function test(T-bilirubin, AST, ALT)is over 3 times than upper normal limit WBC< 2,500/mm^3, or platelet < 75,000/mm^3, or ANC < 1,300/ mm^3 Protein/Creatinine ratio≥1.0(mg/mg) Patents who had a record of taking mTOR inhibitor before 3 months In investigator's judgement