The use of mobile devices in healthcare, or mHealth, has the potential to play an important role in low- and middle-income countries in a wide range of areas. A particular area with great potential to improve global health is using mHealth for data collection. We propose three ideas: (i) to validate and conduct household surveys, (ii) to monitor large-scale programs, and (iii) to measure the global burden of disease. We need to know more about mHealth interventions and their validity to maximise their potential.