Background: Mobile health (mHealth) applications, such as innovative electronic forms on smartphones, could potentially improve the performance of health care workers and health systems in developing countries. However, contextual evidence on health workers' barriers and motivating factors that may influence large-scale implementation of such interfaces for health care delivery is scarce. Methods: A pretested semistructured questionnaire was used to assess health workers' experiences, barriers, preferences, and motivating factors in using mobile health forms on smartphones in the context of maternal health care in Ethiopia. Twenty-five health extension workers (HEWs) and midwives, working in 13 primary health care facilities in Tigray region, Ethiopia, participated in this study. Results: Over a 6-month period, a total of 2,893 electronic health records of 1,122 women were submitted to a central computer through the Internet. Sixteen (69.6%) workers believed the forms were good reminders on what to do and what questions needed to be asked. Twelve (52.2%) workers said electronic forms were comprehensive and 9 (39.1%) workers saw electronic forms as learning tools. All workers preferred unrestricted use of the smartphones and believed it helped them adapt to the smartphones and electronic forms for work purposes. With regards to language preference, 18 (78.3%) preferred using the local language (Tigrinya) version of the forms to English. Indentified barriers for not using electronic forms consistently include challenges related to electronic forms (for example, problem with username and password setting as reported by 5 (21.7%), smartphones (for example, smartphone froze or locked up as reported by 9 (39.1%) and health system (for example, frequent movement of health workers as reported by 19 (82.6%)). Conclusions: Both HEWs and midwives found the electronic forms on smartphones useful for their day-to-day maternal health care services delivery. However, sustainable use and implementation of such work tools at scale would be daunting without providing technical support to health workers, securing mobile network airtime and improving key functions of the larger health system.