The deadliest attack, at 6.30am (0300 GMT) on Wednesday, occurred in Uruba Square, in the Shia pilgrimage district of Kadhimiyah, where day labourers gather in the early morning as they wait to be hired.
At least 80 people died and 162 were wounded, a security official said, citing collated figures from five hospitals.
Around 10am (0600 GMT), another car bomber rammed an Iraqi military convoy, killing three soldiers in al-Adel district of west Baghdad, the official said.
Ten minutes later, a third bomber killed four civilians and wounded 22 in the Shula neighbourhood of northwest Baghdad, he added.
And two US soldiers were wounded at about the same time when a fourth suicide bomber rammed a vehicle packed with explosives into their military Humvee in east Baghdad, a US military spokeswoman said.
A fifth bomber blew himself up at around 8.30am in another part of the city without causing any other casualties, the spokeswoman added.
Casualty wards were overflowing
It was not immediately clear if the bomber had blown up the vehicle prematurely.
Iraqi journalist Ziyad al-Samarai told Aljazeera that reporters were barred from approaching the area and that US and Iraqi forces had cordoned off the targeted areas.
An Iraqi police patrol was also attacked in the new Baghdad area, injuring three policemen, while three others were also wounded while attacked in Palestine Street, al-Samarai reported.
Earlier, armed men dragged 17 people out of their homes in al-Taji just north of Baghdad and killed them, police said.
Reports said the men rounded up their victims in the middle of the night and shot them outside their houses in Taji.
Sectarian killings have raised fears of civil war in Iraq, where fighters are waging a campaign of bombings and
shootings in a bid to topple the US backed government.
Iraqi government officials have also accused Sunni Arabs of attacking Shias, who were swept to power in January elections.
The car bombing in Kadhimiyah
Fighters loyal to al-Qaida’s Iraq frontman said in an internet statement on Wednesday that they had carried out a wave of suicide bombings in Baghdad to avenge an offensive by US and Iraqi government troops on the northern rebel town of Tal Afar.
“The conquest of revenge for the Sunni people of Tal Afar has started,” Abu Musab al-Zarqawi’s al-Qaida Organisation in the Land of Two Rivers said in the statement, whose authenticity could not be verified.
It said its “brigades” had launched a series of attacks, led by its elite “martyrdom-seeking” brigade.
The statement did not claim responsibility for any of the suicide bombings, only promising to “release more (details), God willing, as soon as news comes in of the operations in Baghdad and other cities”.