The attacks are part of a wave of violence that has washed across Iraq since a deadly security crackdown on a Sunni protest camp in April.
Since then, the bloodshed in the country has reached heights unseen since the country teetered on the brink of civil war in 2006 and 2007.
There was no immediate claim of responsibility for today's attacks, but insurgent groups frequently target civilians in markets, cafes and commercial streets in Shia areas in an attempt to undermine confidence in the Shia-led government and stir up Iraq's already simmering sectarian tensions.
The deadliest attack took place in the mostly Shia neighborhood of Baiyaa, where a car bomb exploded inside a mechanic's shop, killing seven people and wounding 14 others, police said.
Another car bomb in a commercial street in downtown Baghdad killed four more people, while in the eastern Ghadeer district another car bomb near a government tax office killed six people and wounded 22, authorities said.
In the Husseiniyah neighborhood, a car bombing near a restaurant killed three people and wounded 13. Another car bomb near a small market in Baghdad's Shia slum of Sadr City killed two, while a blast in a crowded marketplace in the primarily Shia neighborhood of Amil killed five more.
One bombing struck the Sunni neighborhood of Radhwaniya, hitting a row of shops and killing two people and wounding eight, police said.
Also, an off-duty army officer was killed when a sticky bomb attached to his car exploded as he was driving near his house in Madain town, just south of Baghdad, police said.
Saad Maan Ibrahim, an Interior Ministry spokesman said today's attacks bear the hallmark of al-Qaida's Iraqi branch.
"Al-Qaida terrorists have been attacking soft targets because they are not able to confront our security forces," Ibrahim said. "They want to send a message that they are still strong."
Medical officials confirmed the casualty figures for all attacks. All officials spoke on condition of anonymity because they are not authorized to speak to media.
At least 120 people have died in attacks in Iraq so far this month, according to an Associated Press count.