McCain made the comment on CBS's "Late Show with David Letterman" -- an appearance during which he also announced his 2008 presidential bid.
On the program, McCain said, "Americans are very frustrated, and they have every right to be. We've wasted a lot of our most precious treasure, which is American lives."
McCain released a statement today saying, "I should have used the word sacrificed, as I have in the past. No one appreciates and honors more than I do the selfless patriotism of American servicemen and women in the Iraq War."
Democratic presidential Barack Obama contender recently apologized for making a similar "wasted" comment.