How many episodes will there be in season 2 of Fullmetal Alchemist?

Do you mean the 2nd season of the first series(which contains episodes 26-51) or Fullmetal Alchemist:Brotherhood?

If you're talking about Brotherhood, most places have been saying that it'll be 63 episodes long.
However, I haven't found any official announcements confirming that.

Considering how the anime's getting close to catching up with the manga and the manga seems to be near its end, it sounds like a plausible number.

Also, they've announced the 5th OP(Rain by SID) and ED(Ray of Light by Shoko Nakagawa) theme, so it should have ten or so more episodes after those start.
(Unless the manga goes on longer than expected and they throw in some filler episodes, go on hiatus, etc)

you are able to watch the finished Fullmetal Alchemist sequence and The Conquerer of Shamballa on YouTube for unfastened. you additionally can watch the extra moderen (and better) sequence Fullmetal Alchemist: Brotherhood on there besides.

63.