Nonadherence to immunosuppression is a leading cause of late graft rejection, chronic rejection and graft failure and it is regarded as a preventable cause of graft loss after solid organ transplantation. The purpose of this study is to evaluate whether mobile application for drug medication can enhance the drug adherence rate.

Inclusion Criteria:

• 1 year after kidney transplantation
• out-patient follow up in Seoul National University Hospital
• using android smartphone
• taking Prograf as a main immunosuppressant
• 15-70 years

Exclusion Criteria:

• patients who cannot use medication event monitoring system
• multiorgan transplant
• immunosuppression medication change within 4 weeks of randomization
• caregiver management of the medication regimen
• pregnancy
• patients who can not use mobile application