Officials say at least 14 blasts went off in 11 neighborhoods around the city, leaving 65 dead and 176 others injured.
Authorities say the blasts ranged from sticky bombs attached to cars to roadside bombs and vehicles packed with explosives. There was at least one suicide bombing.
The apparently coordinated attacks come amid a political crisis between Iraq's Sunni and Shiite factions. The bombings may be linked more to the U.S. withdrawal than the political crisis, but all together, the developments heighten fears of a new round of Shiite-Sunni sectarian bloodshed like the one a few years back that pushed Iraq to the brink of civil war.
There was no immediate claim of responsibility, but the attacks bore all the hallmarks of al Qaeda's Sunni insurgents. Most of the bombings hit Shiite neighborhoods.
The Associated Press contributed to this report.