March saw a rise in bombings and heavy fighting in Basra
The monthly figure of people killed in Iraq rose by 50% in March compared with the previous month, according to official government counts.
A total of 1,082 Iraqis, including 925 non-combatant civilians, were killed, up from 721 in February.
The figures come from the combined counts of the health, defence and interior ministries.
March also saw an increase in bombings and intense fighting between Shia militiamen and government forces.
The number of deaths last month seems to confirm a trend of rising deaths due to violence.
More than 1,800 people were killed in August 2007. This declined to 540 in January 2008, but the figure has risen steadily since.
Although most victims appear to have been civilians, the rise in death rates among Iraqi troops and police was comparatively higher.
One hundred and two policemen and 54 soldiers were killed, compared with 65 and 20 respectively in February. The government says 641 suspected insurgents were killed.
Correspondents say the figures will be a blow to the Baghdad government and the US, which had claimed overall levels of violence had been reduced by last year's US troop surge.
Hundreds of people died in fighting last week in the southern city of Basra after Prime Minister Nouri Maliki ordered a crackdown on Shia militias.
Reports say many of the dead were civilians caught in the crossfire.
The spiritual leader of the Mehdi Army militia, Moqtada Sadr, has ordered his fighters off the streets in a deal with the authorities, who agreed to stop rounding them up.
Mr Maliki hailed the crackdown as a "success" and pledged to recruit 10,000 extra troops to keep order in Basra.