In the panoply of European institutions that have been criticized for their secrecy and lack of accountability, the European Council of Ministers certainly ranks near the top of the list. However, others insist that the secrecy of the policy process within the European Union is exaggerated, and that the public already has access to plentiful information about decision making. This chapter examines empirical evidence that may be used to determine the extent to which secrecy of the EU Council of Ministers is costly or beneficial. It also discusses the effect of efforts made by the Council since 1993 to become more open in its proceedings. Though the focus of the chapter is on whether contributions of individual members of a decision-making body are observable, there are more basic levels of transparency that might be considered, in particular whether there is a ‘giving reasons requirement’, whereby a decision-making body is obliged to provide an explanation for its decisions.