Om is a duo formed in 2003 by the rhythm section of the disbanded stoner doom metal band Sleep. The band's first three albums feature Al Cisneros on vocals and bass and Chris Hakius on drums. Their music is similar in structure to Tibetan chanting.
In December 2007 the band performed in Jerusalem, their performance lasting over five hours in duration. A portion of that show was released on 12" vinyl by Southern Lord "OM - Live at Jerusalem." Their 2007 album Pilgrimage was chosen as Mojo Magazine's Underground Album of the Year.
On January 31, 2008 Hakius left the band and was replaced by drummer Emil Amos. OM has since released a single featuring the song Gebel Barkal accompanied by the band's b-side dub mix, "Version." This is the first OM release to feature Amos. The 7" 45 was released August 15, 2008 on Sub Pop.