Informed decision-making (IDM) is considered an important ethical and legal requirement for population-based screening. Governments offering such screening have a duty to enable invitees to make informed decisions regarding participation. Various views exist on how to define and measure IDM in different screening programmes. In this paper we first address the question which components should be part of IDM in the context of cancer screening. Departing from two diverging interpretations of the value of autonomy—as a right and as an ideal—we describe how this value is operationalized in the practice of informed consent in medicine and translate this to IDM in population-based cancer screening. Next, we specify components of IDM, which is voluntariness and the requirements of disclosure and understanding. We argue that whereas disclosure should contain all information considered relevant in order to enable authentic IDM, understanding of basic information is sufficient for a valid IDM. In the second part of the paper we apply the capability approach in order to argue for the responsibility of the government to warrant equal and real opportunities for invitees for IDM. We argue that additional conditions beyond mere provision of information are needed in order to do so.