Despite significant advances in the care of kidney transplant recipients (KTRs), long-term graft survival remains poor. Medication non-adherence (MNA) to immunosuppressant's and uncontrolled hypertension (HTN) are predominant risk factors for premature graft rejection, graft loss, and death. Efforts to improve MNA and BP control in KTRs have met with limited success. Innovative approaches are needed that are acceptable, sustainable, efficacious, and easily disseminated. There have been no randomized controlled trials (RCTs) evaluating the application of theory-driven and individually tailored mobile health (mHealth) technology programs among KTRs with MNA and uncontrolled HTN. The proposed research will test and refine the Smart phone Medication Adherence Saves Kidneys (SMASK) program. SMASK includes multi-level components: 1) automated reminders from an electronic medication tray; 2) tailored text message/voice mail motivational feedback and reinforcement guided by self-determination theory and based upon adherence to daily medication and BP monitoring and 3) automated summary reports and direct alerts to providers. A 6-month, 2- arm (SMASK vs. enhanced Standard Care [SC]) efficacy RCT will be conducted in 116 MNA KTRs with uncontrolled HTN. Evaluations will occur at pre-intervention, months 3 and 6, and post-trial follow-ups at months 12 and 18. Specific aims are to test the hypotheses that, compared to the SC cohort, the SMASK cohort will demonstrate significantly improved and sustained changes at months 3, 6, 12, and 18 in: 1) Primary Outcome Variables: a) Medication adherence: % with electronic monitor-derived adherence scores >0.90; b) BP control: % reaching and sustaining KDIGO guidelines for BP control (clinic resting BP <130/80 mmHg). 2) Secondary Outcome Variables: a) Provider adherence to KDIGO guidelines as measured by timing of medication changes; b) Changes in Self-Determination Theory constructs (e.g., competence and autonomous regulation). 3) Exploratory Outcome Variables: a) Estimated glomerular filtration rate; b) Degree of graft fibrosis; c) Variability in calcineurin inhibitor trugh levels; d) % reaching and sustaining 24-hr ambulatory BP<130/80 mmHg. After 6-month trial completion evaluation, focus groups with random sample of SMASK subjects (n=20) and healthcare providers (3-5) will assess key user reactions including acceptability, usability, salience and aids/barriers to sustainability. Data from RCT and focus groups will be triangulated to further refine and optimize SMASK and prepare for a multi-site effectiveness RCT. Our long-term objective is to reduce premature graft loss among KTRs by developing effective and sustainable mHealth secondary prevention self-management programs for medication adherence and bio-function monitoring (e.g., BP).