The six car bombs, which hit five different areas of the Iraqi capital, also wounded more than 100 people.
The deadliest single attack was in Sinaa Street in the city's central Karrada district, and killed at least 10 people.
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Two car bombs also hit the Amil area of south Baghdad, and one each exploded in Ameen in the east, Zafraniyah in the centre and Sadr City in the north.
Baghdad is hit by near-daily bombings and shootings, some of which have been claimed by the Islamic State (IS) jihadist group, which has overrun large parts of the country since June.
IS and other Sunni extremist groups consider Shiites to be heretics and frequently target them.
The jihadists would have to make major advances to even attempt to occupy part of the Iraqi capital, but security forces are unable to keep them from carrying out bomb attacks.