Parliamentary approval can be of crucial importance to ensure the democratic legitimacy of military operations as it can establish public consent to the executive's use of force. But involving parliament in decisions to deploy military forces may have negative repercussions on the efficiency of operations, e.g. by slowing down decision-making. As the military activity of democracies has been on the rise since the end of the Cold War, democracies around the world have been increasingly pressed to deal with this trade-off between legitimacy and efficiency in sending troops abroad. This paper surveys the deployment provisions of 49 contemporary democracies to establish whether and how parliaments are actually involved in deployment decisions. It demonstrates that the rules for parliamentary participation mark a continuum that ranges from complete exclusion to a comprehensive veto position of parliament over all potential deployments. In between these two extremes, democracies have found a wide variety of solutions to cope with the legitimacy-efficiency problem. Despite the growing prevalence of military deployments, there is no discernible trend towards parliamentarisation, however. Rather the trend towards internationalisation of security policies contributed to a weakening of parliamentary powers in some countries. © 2010 The Author.