The attacks in Hillah began with a roadside bombing near tents commemorating the 17th century death of the Prophet Muhammad's grandson, Imam Hussein. Shorty after, a car bomb targeting emergency response teams went off.
The roadside and car bombs, which occurred in a busy commercial area, killed at least 29 people and wounded as many as 90, a police officer said. This marks the deadliest attack in the city this year.
Hours earlier, a parked car exploded near a shrine in the Shitte city of Karbala, killing six people and wounding 20, another police officer said.
Karbala is one of the holiest cities in Shiite Islam, and hundreds of thousands of Shiites flock to their golden-domed shrines every year.
Such religious ceremonies have often been targeted by Sunni insurgents seeking to foment sectarian violence and undermine the Shiite-led government.
Also, a suicide bomber drove his explosives-laden car into a police checkpoint in the mainly Sunni city of Fallujah, killing three policemen and wounding 11 others, a police official said.
In the north city of Mosul, a parked car bomb exploded as a police patrol passed, killing two people and wounding two others. In the town of Balad Ruz, another police patrol was hit by a roadside bomb, killing one policeman and wounding six others.
In Taji, north of Baghdad, a roadside bomb killed an Iraqi soldier and wounded five others, and a parked car bomb struck a restaurant in Madain, killing a civilian and wounding 12 others.
The nationwide death toll was the highest since Oct. 27 when 40 people were killed in a string of bombings and other attacks around the country.
The Associated Press contributed to this report.