Ten bombings mainly targeting Shi'ite-majority areas of Baghdad province have killed at least 41 people, while 20 have died in bombings and shootings elsewhere in Iraq.
The attacks are the latest in a surge in violence that has killed over 650 people so far this month, and more than 5350 this year.
Nine blasts hit different areas in and around Baghdad on Sunday and also wounded more than 110 people, security and medical officials say.
One of the worst-hit neighbourhoods was Shaab in north Baghdad, where two car bombs exploded in a commercial area, killing at least eight people and wounding at least 18.
Blasts also struck the areas of Bayaa, Baladiyat, Mashtal, Hurriyah and Dura in Baghdad, and Saba al-Bur, Nahrawan and Tarmiyah near the capital.
The Mashtal blast hit a bus station while bombs in Bayaa, Dura, Saba al-Bur and Tarmiyah targeted commercial areas.
Sunni militants often carry out attacks against members of Iraq's Shi'ite majority, whom they consider apostates.
Iraq has since last month restricted many Baghdad residents to using their cars only every other day, but the measure has failed to prevent dozens of vehicle bombs exploding in the capital.
In the northern city of Mosul, a car bomb targeting soldiers waiting outside a bank to collect their wages killed at least 14 people, among them three soldiers, and wounded more than 30 people.
Unknown gunmen also shot dead two soldiers and a civilian in two separate attacks in Mosul, while a car bomb exploded near an army checkpoint in the city, killing a woman and wounding eight people.
And gunmen killed two Shi'ite civilians in the Muqdadiyah area, northeast of the city of Baquba.
Violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a brutal sectarian conflict.
