The Cardassian Intelligence Bureau was the Cardassian Union's intelligence agency while the Union was a member state of the Dominion. This agency was a successor to the Obsidian Order

After a distarous strike on the Founder's homeworld, the Obsidian Order and the Romulan's Tal Shiar intelligence agency had been reduced to almost nothing. The Obsidian Order faced the worst outcome between the two agencies as it was eventually forced to disband. During the Dominion War the Cardassian Intelligence Bureau took the place of the Obsidian Order, and absorbed some of its personnel and equipment. (DS9 episodes: Improbable Cause & The Die is Cast).

Alon Ghemor became the leader of the Intelligence Bureau (DS9 novel: The Never-Ending Sacrifice)