Hmmmmm thats a tough one, since there are so many positions from so MANY games!
How many chess positions do you think there are in chess

It can't be infinite since the number of pieces and squares are both finite. But it's much more than 1,500,000.
If you want to simplify, all the pieces but the kings, the bishops and the pawns can be on any of the 64 squares provided there is no mutual check. (The bishops can only be on their color, the pawns can't be on the first and last rows and some other squares are unreachable for them, the kings can't touch each other).
Take one Queen on a board: 64 positions
Two queens, different colors: 64²= 4096
Two queens, Two rooks, Two knights, different colors every time: 64^6= 68 719 476 736 already
That was the easy part. Now you can't do the same for same pieces from the same colors since they are equivalent (not the bishops) nor for the pieces I talked about before.
Then you have to take into account castling, promotions...
Not infinite but pretty high and impossible to calculate. I wonder if someone ever managed to do the maths...
http://en.wikipedia.org/wiki/Shannon_number
Seems the current upper bound is "2^155, which is less than 10^46.7"
I know the possible number of games is 10 to the 120th power, but I don't know about positions.
I think I gave the correct answer, so now you know.

http://www.chess.com/blog/Pau/how-many-possible-games-are-there?_domain=old_blog_host&_parent=old_frontend_blog_view
This article states that there is a "Shannon Number" of possible chess games. Which is 10 raised to the 120th.
I would venture there are fewer stars in the universe, than there are games on the chess board.

http://www.chess.com/blog/Pau/how-many-possible-games-are-there?_domain=old_blog_host&_parent=old_frontend_blog_view
This article states that there is a "Shannon Number" of possible chess games. Which is 10 raised to the 120th.
I would venture there are fewer stars in the universe, than there are games on the chess board.
Fewer stars!!??!!?? There are only about10 to the 79th power atoms in the observable universe, so there are far less electrons in the universe than there are possible chess games.
I would have to say 1,500,000 what do you think? Or do you think it is infinite.