 Use of mobile cellular devices has grown rapidly worldwide, increasing from 2 billion subscriptions in 2005 to an estimated 5.3 billion at the end of 2010.9 The promise of mobile health mHealth technologies for strengthening health care delivery in resource-limited settings has been acknowledged by the United Nations Joint Programme on HIVAIDS UNAIDS in development of its strategic plan. Short Message Service SMS text messages were recently shown in a large randomized trial to be an effective intervention for smoking cessation. Text messages have also been effectively utilized to improve attendance at clinic appointments, although few data are available from HIV clinics. ART dose reminder messages sent with pagers or mobile phones have been used in several settings to improve adherence. Two recent randomized mHealth studies in sub-Saharan Africa have demonstrated benefit of weekly text messages for improving adherence and rates of viral suppression. Additional randomized trials of SMS adherence reminders are under development in India and Cameroon. 