The Lancet

In October of 2004 The Lancet published a study titled "Mortality before and after the 2003 invasion of Iraq: cluster sample survey" which provided an estimate that 98,000 Iraqis have died because of the invasion and occupation of Iraq. This estimate (usually approximated to 100,000 deaths) includes all causes of death, both violent and nonviolent.

Study Shows Civilian Death Toll in Iraq More Than 100,000

...I’m even more struck that here a year after our study came out, the first time the President has been asked about this was not by a reporter, but by someone from the public when he took a question.
-Les Roberts

On the 1,000th day of the U.S. war on Iraq, we look at a subject that usually receives little attention -- the Iraqi civilian death toll since the war began. We speak with Dr. Les Roberts, the lead researcher of a study released last year on the number of deaths in Iraq, which put the toll at more than 100,000. [includes rush transcript] President Bush was asked about the Iraqi civilian death toll on Monday following his speech at the Philadelphia World Affairs Council.

Q: Since the inception of the Iraqi war, I'd like to know the approximate total of Iraqis who have been killed. And