Mobile phones, especially with connectivity provided by rapidly expanding 3G networks, can be transformative in the quest for accurate and reliable health data in developing countries. Consequently, a plethora of efforts in the Information and Communication Technologies for Development (ICTD) field are focused on collecting, aggregating and digitizing community health information with the ultimate goal of strengthening resource-constrained health care systems. Such ventures often work in conjunction with Community Health Worker (CHW) programs to address the last-mile challenge of reaching rural communities. While leading such ventures in East Africa and South East Asia over the last six years, we have learned the importance of understanding and addressing a wide set of interrelated contextual, communication, business, and technological challenges to data collection. Drawing from these real-world experiences, this article presents the spectrum of challenges that entrepreneurs need to tackle for their data-driven health care ventures to be successful. An example-centric approach is employed with several examples drawn from the Mashavu Telemedicine System in Kenya. Mashavu regressed technologically from one pilot to the next, culminating in a health care delivery venture that is economically sustainable but uses almost no technology and does not collect any data.