Iraqi officials said dozens more were injured and the death toll was expected to rise. The coordinated bombings targeted religious processions during an annual pilgrimage at four different locations across Baghdad.
Nobody immediately claimed responsibility for the attacks, but they bore the hallmarks of Sunni insurgents who frequently target Shiites in Iraq.
The latest bombing is the third attack in the capital this week. Wednesday was one of the deadliest days in Iraq since U.S. troops withdrew from the country.
The Associated Press contributed to this report.