Abstract-Lowering blood pressure reduces cardiovascular risk, yet hypertension is poorly controlled in diabetic patients.In a pilot study we demonstrated that a home blood pressure telemonitoring system, which provided self-care messages on the smartphone of hypertensive diabetic patients immediately after each reading, improved blood pressure control. Messages were based on care paths defined by running averages of transmitted readings. The present study tests the system's effectiveness in a randomized, controlled trial in diabetic patients with uncontrolled systolic hypertension. Of 244 subjects screened for eligibility, 110 (45%) were randomly allocated to the intervention (nϭ55) or control (nϭ55) group, and 105 (95.5%) completed the 1-year outcome visit. In the intention-to-treat analysis, mean daytime ambulatory systolic blood pressure, the primary end point, decreased significantly only in the intervention group by 9.1Ϯ15.6 mmHg (SD; PϽ0.0001), and the mean between-group difference was 7.1Ϯ2.3 mmHg (SE; PϽ0.005). Furthermore, 51% of intervention subjects achieved the guideline recommended target of Ͻ130/80 mmHg compared with 31% of control subjects (PϽ0.05). These improvements were obtained without the use of more or different antihypertensive medications or additional clinic visits to physicians. Providing self-care support did not affect anxiety but worsened depression on the Hospital Anxiety and Depression Scale (baseline, 4.1Ϯ3.76; exit, 5.2Ϯ4.30; Pϭ0.014). This study demonstrated that home blood pressure telemonitoring combined with automated self-care support reduced the blood pressure of diabetic patients with uncontrolled systolic hypertension and improved hypertension control. Home blood pressure monitoring alone had no effect on blood pressure. 3 Such results spurred development of chronic care models that engage patients in their own care. 4 Home BP monitoring promotes self-care, improves BP control, and is endorsed by several prominent organizations as an adjunct to hypertension treatment. 5 A recent meta-analysis suggested that adding telemonitoring to self-measurement of BP is even more effective in reducing BP. 6 In the telemonitoring studies, however, a physician or member of the healthcare team reviewed the transmitted data and contacted the patients to adjust antihypertensive treatment.7-13 Thus, it is unclear whether the better outcome was related to the use of a telemonitoring system or the increased involvement of healthcare providers in the treatment process.Previously we reported the development of a home BP telemonitoring system that provided self-care messages on the smartphone of patients immediately after each reading. A.G.L. had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. None of the other authors has real or perceived conflicts of interest related to the study.This trial has been registered at www.clinicaltrials.gov (identifier NCT00717665 eliminate the need for a health provider to re...