Karpov and Kamsky agreed to a draw in the 67th move of a
game which had been carried over from Wednesday.
Karpov, 45, needs at least three more wins and a draw in the 20-game match to keep his World Chess Federation (FIDE) title. The 12th game is Friday.
Kamsky, 22, who defected from the Soviet Union to the United States in 1988, is challenging Karpov in Elista, capital of Russia's semi-autonomous Kalmyk Republic, near the Caspian Sea.
Players win one point for victory and half a point for a draw. If they are level after 20 games, the match will continue until one of them wins another game.
Victory for either contestant will be tainted by the absence
of world number one Garry Kasparov, who is not challenging
because of a split with FIDE.