It’s the highest level since January, after a US troop build-up for the Iraqi elections in December 2005.
A Pentagon spokesman attributed the growth in size of the force to overlapping unit rotations but the stepped-up operations have so far failed to bring the violence under control.
The number of US servicemen and women killed in Iraq in October has hit 103, in one of the bloodiest months since the 2003 invasion.
In all, 61 US army soldiers, 31 marines, two navy sailors and an airman have been killed in action, while two soldiers and a marine have died of "non-combat related causes," the US-led coalition said.
Four non-American coalition soldiers were also killed.
In addition, five US civilians were killed in attacks, bringing the monthly toll for the coalition as a whole to 106.
Before the latest death, October was already the deadliest month since January 2005 when 107 US troops were killed.
The highest monthly toll was in November 2004 when 137 deaths were recorded.
The total number of US deaths in Iraq since the US-led invasion in March 2003 is 2,813. Iraqi security forces have suffered even greater casualties.
Election woes
US President George W Bush is facing mounting pressure over his Iraq policy ahead of next week’s mid-term congressional elections in which his Republicans could easily lose control of both houses.
US Vice President Dick Cheney claims the increase of violence in
Iraq is linked with efforts to influence the outcome of next week's elections.
"It's my belief that they're very sensitive of the fact that we've got an election scheduled and they can get on the websites like anybody else," Mr Cheney said.
He said al-Qaeda and other elements were trying to "break the will of the American people" because "they think we don't have the stomach for the fight long-term."
Asked if the attacks were timed to influence the US elections, Cheney said, "That's my belief."
Tentative grip
Now in its fourth year, the Iraq war is a political liability for Mr Bush and Republican allies, who control the House of Representatives and the Senate. The Democrats need to take 15 House seats and six Senate seats in the election to win control of both chambers.
Mr Cheney, who 17 months ago said the insurgency was in its last throes, said that "there's going to be probably a continued level of violence for some considerable period of time in Iraq."
He said that unlike other wars, it was unlikely there would be some dramatic turning point that signals progress.
"There is progress," Mr Cheney said. "It's just - you're not going to see the kind of thing ... a victory like Midway in World War II where we sank all the enemy carriers, or a surrender ceremony at the end of the war. It's the kind of thing where you have to keep grinding it out day after day after day. It's tough."