The attacks come amid rising sectarian discord in Iraq and appear aimed at shaking Iraqis’ confidence in the Shiite-led government.
The explosions struck at the start of the local working week and primarily targeted outdoor markets.
Violence in Iraq has fallen since the height of sectarian fighting in 2006 and 2007, but insurgents still frequently launch lethal attacks against security forces and civilians.
It was at least the third time this month that attacks have claimed more than 20 lives in a single day.
The detonation of a parked car loaded with explosives in the sprawling Shiite district of Sadr City heralded the start of the attacks yesterday morning. Two more parked cars later exploded elsewhere in the neighbourhood.
Nima Khadum, a government employee who lives in Sadr City, said the explosions shattered the windows of his house.
He said the air afterwards was heavy with smoke while burning cars littered the street and the bodies of the dead and wounded lay nearby.
Mr Khadum added: “The scene was a bloody one that brought to my mind the painful memories of the violent past.
“I don’t see the benefit of security checkpoints that only cause traffic jams and don’t do anything to secure Baghdad.
“The government, with its failing security forces, bears full responsibility for the bloodshed today.”
Police and hospital officials said more than 130 people were wounded in the explosions.