What episode does full metal alchemist brotherhood start?

There's no specific episode where *Fullmetal Alchemist: Brotherhood* "starts." It's a separate series from the original *Fullmetal Alchemist* and has its own storyline and episodes.

It's best to think of them as two different adaptations of the same manga.

* Fullmetal Alchemist (2003) is the first anime adaptation, which deviates from the manga after a certain point.

* Fullmetal Alchemist: Brotherhood (2009) is a more faithful adaptation of the entire manga, telling a different story from the 2003 version.

So, you should start with *Fullmetal Alchemist: Brotherhood* from episode 1.