Interactive voice response and text message (IVR-T) technology may improve hypertension control in under-resourced settings. We conducted a randomized clinical trial to determine whether an IVR-T intervention would improve blood pressure (BP), medication adherence and visit keeping among adults with hypertension from multiple racial and ethnic groups in primary care at an Urban Indian Health Organization in Albuquerque, New Mexico. Two hundred and ninety-five participants were randomly assigned to IVR-T (N = 148) or to usual care (N = 147). The IVR-T arm received reminders for clinic visits, messages to reschedule missed clinic visits, monthly medication refill reminders, weekly motivational messages, and a blood pressure cuff. The usual care arm received no messages. The primary outcome was change in systolic BP (SBP) between baseline and 12 months. Secondary outcomes included change in SBP between baseline and 6 months, change in diastolic BP (DBP) at 6 and 12 months, self-reported adherence at 6 months, and the proportion of missed primary care clinic appointments. The intervention did not affect SBP or DBP at 6 or 12 months. The 12-month change in SBP/DBP was 1.66/1.10 mm Hg in usual care and 0.23/1.34 mm Hg in the intervention group (P values = .57 and .88, respectively). Self-reported medication adherence improved comparably in both groups, and there was no difference in percentage of kept visits. Several features of study design, clinic operations, and data transfer were barriers to demonstrating effectiveness.© 2020 Wiley Periodicals LLC.