This short paper offers some reflections on the role, effectiveness and challenges for health information systems in developing countries. It is argued that such systems need to support the use of information for action, but that this is often compromised by poor quality data. In addition, good data and related ICTs are inadequate by themselves since effective action also needs knowledgeable people and supportive institutions. Some approaches are discussed on software philosophy, educating people and changing institutions. The paper also includes a brief reflection on theory and its role in relation to action in health information systems, and ends with some reflections for practice. Illustrative examples in the paper are drawn mainly from India, but the issues discussed are relevant to engagement across the globe.