The study investigated how the opposition in the German Bundestag used the available means and instruments to perform oppositional control in security and defense politics, and which topics they prioritized between 1998 and 2009. The fundamental rationale behind this research is due to hitherto limited scholarly research on the opposition in the Bundestag in general and the role of parliaments in the policy area examined in particular. By evaluating parliamentary documents, thematic categories were elicited and analyzed in three spheres (parliamentary, public, legal) along a theoretical chain of control according to Steffani as part of a qualitative content analysis. The results were evaluated for each election period as well as for the entire study period. The core issues of the 14th electoral period were arms exports, military operations abroad, and Bundeswehr reforms. The opposition showed consistent control behavior responding to government action. The PDS-faction implemented a chain of control related to operations abroad. While the 15th electoral term was marked by less control activity overall, the focus regarding missions abroad shifted to parliamentary participation rights as well as conscription and community service. The parliament concentrated its attention on the successful organization of foreign assignments, not solely their justification. The three opposition factions during the so-called grand coalition between CDU/CSU and SPD during the 16th electoral period focused on their own party priorities given their few substantial overlaps. With a government that was not very proactive in security and defense policy, the opposition acted primarily as an agenda-setter. In doing so, it went beyond a mere alternative function, bringing forward future-oriented issues. The focus was on missions abroad (esp. the developments in Afghanistan and new mandates on the African continent), domestic operations, and equipment for the Bundeswehr. The study shows that the opposition was primarily prioritizing party issues and the majority of the control topics were limited to the respective election periods, especially when it came to internal Bundeswehr issues, e.g. decisions on locations of barracks. Nevertheless, especially the 16th electoral period illustrated that the opposition was not just reacting. She set topics in the political field that would shape future debates, e.g. strategy, equipment and parliamentary participation in missions abroad, the use of drones or armaments management. The results made it clear that the opposition is an important protagonist in this policy area, which is usually dominated by the executive branch. Further scientific analysis of the opposition is still necessary in order to better research the democratic processes in security and defense policy.