Background In rural areas in China and India, cardiovascular disease burden is high but economic and healthcare resources are limited. This study aims to develop and evaluate a simplified cardiovascular management program (SimCard) delivered by community health workers (CHWs) with the aid of a smartphone-based electronic decision support system. Methods and Results The SimCard study was a yearlong cluster-randomized controlled trial conducted in 47 villages (27 in China and 20 in India). 2,086 ‘high cardiovascular risk’ individuals (aged 40 years or older with self-reported history of coronary heart disease, stroke, diabetes, and/or measured systolic blood pressure ≥160 mmHg) were recruited. Participants in the intervention villages were managed by CHWs through an Android-powered “app” on a monthly basis focusing on two medication use and two lifestyle modifications. Compared with the control group, the intervention group had a 25.5% (P<0.001) higher net increase in the primary outcome of the proportion of patient-reported anti-hypertensive medication use pre-and-post intervention. There were also significant differences in certain secondary outcomes: aspirin use (net difference 17.1%, P<0.001) and systolic blood pressure (−2.7 mmHg, P=0.04). However, no significant changes were observed in the lifestyle factors. The intervention was culturally tailored and country-specific results revealed important differences between the regions. Conclusions The results indicate that the simplified cardiovascular management program improved quality of primary care and clinical outcomes in resource-poor settings in China and India. Larger trials in more places are needed to ascertain potential impacts on mortality and morbidity outcomes. Clinical Trial Registration Information clinicaltrials.gov. Identifier: NCT01503814.