Bombers struck in the capital's multi-religious south-eastern neighbourhood of Jadid on Wednesday, killing 23 people and wounding 58 by blowing up a car on the main road near a market.
Six others were killed in separate bombings and shootings across the country, leaving a total of at least 29 dead on Wednesday.
The upsurge in violence reinforced fears of a return to sectarian bloodletting that followed the bombing of a Shi'ite shrine last week.
Hundreds were killed in the ensuing violence that pitted minority Sunnis against Shi'ites.
One of the bloodiest attacks was a car bomb on Tuesday outside a Shi'ite mosque in Baghdad's north-western al-Hurriya neighbourhood, which killed 25.
That blast came just hours after three bombs exploded in quick succession in mixed Shi'ite-Sunni areas in the capital, killing another 30 people.
The new violence jolted frantic US and Iraqi efforts to restore stability to Iraq after the lifting of a curfew on Monday.
US State Department coordinator on Iraq James Jeffrey said US and Iraqi security forces had brought the situation under control nearly a week after the bombing of the Shi'ite shrine that touched off the burst of communal carnage.
"Right now, by Iraq's standards, it's calm and back to normal," Jeffrey said after six days of sectarian violence.