A roadside bombing in the central city of Hilla, south of Baghdad, martyred 30 and injured 80. A second bomb exploded as rescuers arrived at the scene.
It is thought that all the victims were Shia, making this the second bombing this week to target the sect. As yet, no group has claimed responsibility for the attack.
In Karbala, where many people gathered for Ashura, a car bomb was detonated, martyred five and injuring 13.
Bombs also exploded in Fallujah and Mosul where it is believed the police and security services were the target.
Wahhabi terrorists in Iraq often attack Shias, but violence is down markedly compared to 2006 and 2007.
Violent attacks remain common though and fears are high that the recent surge in violence could see the country slide back to the days after the fall of Saddam Hussein, when targeted bombings and shootings were common.