Rates of chronic diseases will continue to rise in developing countries unless effective and cost-effective interventions are implemented. This review aims to discuss the impact of mobile health (m-health) on chronic disease outcomes in low- and middle-income countries (LMIC). Systematic literature searches were performed using CENTRAL, MEDLINE, EMBASE, and LILACS databases and gray literature. Scientific literature was searched to identify controlled studies evaluating cell phone voice and text message interventions to address chronic diseases in adults in low- or middle-income countries. Outcomes measured included morbidity, mortality, hospitalization rates, behavioral or lifestyle changes, process of care improvements, clinical outcomes, costs, patient-provider satisfaction, compliance, and health-related quality of life (HRQoL). From the 1,709 abstracts retrieved, 163 articles were selected for full text review, including 9 randomized controlled trials with 4,604 participants. Most of the studies addressed more than one outcome. Of the articles selected, six studied clinical outcomes, six studied processes of care, three examined healthcare costs, and two examined HRQoL. M-health positively impacted on chronic disease outcomes, improving attendance rates, clinical outcomes, and HRQoL, and was cost-effective. M-health is emerging as a promising tool to address access, coverage, and equity gaps in developing countries and low-resource settings. The results for m-health interventions showed a positive impact on chronic diseases in LMIC. However, a limiting factor of this review was the relatively small number of studies and patients enrolled, highlighting the need for more rigorous research in this area in developing countries.