Officials said the attacks occurred in quick succession after Friday prayers.
Police colonel Hassan al-Baldawy said at least six people were killed and 45 wounded when a suicide bomber detonated an explosives vest in a market near a shrine in the centre of the town and two motorcycle bombers struck near a post office and a police station.
Doctor Khaled Ismail said his hospital in Balad had received seven dead and 44 wounded, including 10 in a critical condition.
Another police source, who declined to be named, said 13 people had been killed and more than 50 wounded in the attacks.
June has seen some of Iraq's worst violence since US troops withdrew in December, with nearly 200 killed, mainly in bomb attacks.
"My wife Amena went to the market at dusk to visit some clothes shops. Suddenly she was thrown to the ground because of the explosion," said Abdul Kareem Mohammed, 56.
"She was wounded in the shoulder and the head. Her clothes are covered in blood. It was a horrible, big explosion."
Sectarian attacks have eased since a peak in 2006-2007 but recent bombings accompanied by heightened political tension have raised concerns Iraq could slip back into worse violence.
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