Health Information Systems are an important component of Health Systems. They are also often the weak link of these systems. Thus, strengthening their performance is crucial in order to improve Health Systems. Solthis is a French NGO, that provides technical support for Health System Strengthening for HIV care in some of the weakest Health Systems in the world (Niger, Mali, Guinea, Sierra Leone). Its support encompasses six main intervention areas : medical skills, procurement and supply systems, laboratories, health information systems, operational research and health system governance. This seminar will be the occasion to share the experience of Solthis about the issues of Health Information System strengthening and the responses that can be implemented. The main issues are the choice of the goals that should be given to these systems (public health oriented vs M&E oriented), the tools that should be used (paper based vs computer based), and their evaluation. The specific questions raised by HIV and the management of chronic disease data in low resource countries will also be discussed.