ABSTRACT: BACKGROUND:Social support interventions can improve diabetes self-care, particularly for Latinos, but are time and resource intensive. Mobile health may overcome these barriers by engaging and training supporters remotely. METHODS:We conducted a randomized controlled feasibility trial of emergency department patients with diabetes to determine the feasibility of enrolling patients and supporters, acceptability of the intervention, and preliminary efficacy results to power a larger trial. All patients received an existing mHealth curriculum (TExT-MED). After identifying a supporter, patients were randomized to intervention: supporters receiving FANS (family and friends network support), a text message support curriculum synchronized to patient messages, or control: supporters receiving a mailed pamphlet of the same information. Participants followed up at 3 months. FANS intervention participants came to postintervention interviews as part of a qualitative analysis. RESULTS:We enrolled 44 patients (22 per arm) and followed up 36 at 3 months. Participants were positive about the program. FANS intervention improved HbA1c (intervention mean decreased from 10.4% to 9.0% vs. from 10.1% to 9.5%, delta -0.8%, confidence interval [CI] -0.4 to 2, P?=?0.30), self-monitoring of glucose (intervention increased 1.6 days/week vs. control decreased 2 days/week, delta 2.3 days/week, CI 4-0.6, P?=?0.02), and physical activity (mean Godin leisure time activity score improved 16.1 vs. decreased 9.6 for control, delta 25.7, CI 49.2-2.3, P?=?0.10). In qualitative analysis, patients reported improved motivation, behaviors, and relationships. Supporters reported making healthier decisions for themselves. CONCLUSIONS:mHealth is a feasible, acceptable, and promising avenue to improve social support and diabetes outcomes.