The mourners, who are from different parts of Iraq, also renew allegiance to the objectives of the movement of Imam Hussein (AS).
Most of them mourn the martyrdom of Imam Hussein (AS) and his companions in the 680 Battle of Karbala with Zanjir Zani (beating oneself with chains).
Arbaeen, which is one of the largest religious gatherings in the world, comes 40 days after Ashura, the martyrdom anniversary of Imam Hussein (AS).
Each year, a huge crowd of Shias flock to the Iraqi city of Karbala to perform mourning rites.
This year Arbaeen falls on Thursday, October 8.
More than thirteen centuries ago, Imam Hussein (AS) was martyred along with dozens of his companions during a last-stand battle against the tyrant of the time, Yazid I.
Imam Hussein (AS) is consequently a highly-venerated figure remembered not only among Shia Muslims but also among Sunnis and people of other faiths.
The following photos show mourners in Bain-ul-Haramain, an area between the holy shrines of Imam Hussein (AS) and Hazrat Abbas (AS).