The application of information and communication technologies (ICT) in health, eHealth, has demonstrated significant opportunities for the improvement of health care services. However, the development of eHealth services requires a framework of policies, resources, infrastructure, and the joint work of ICT specialists and health workers, conditioned by the characteristics of the existing health services. This work proposes a set of critical success factors (CSFs) for evaluating the conditions for health services, to accomplish eHealth projects or programs. It starts with the establishment of a health care service domain, eHealth scope and contributions, prior to the identification of key topics of eHealth initiatives, and the establishment of every CSF, based on guiding questions and metrics. The definition of the CSFs facilitates the exploration of health care services context, to identify gaps and opportunities of strengthening for the future implementation of an eHealth service initiative. Finally, the approach for the evaluation and application of CSFs in a case study is described.