"Machine Messiah" is a song written and recorded by the British progressive rock band Yes. It is the opening track on their tenth studio album Drama. It was brought to the group by Trevor Horn and Geoff Downes, but received extensive input from the other three band members (Chris Squire, Steve Howe, and Alan White). The writing credit for the song went to all five members, as it did for all songs on the album.
Yes used "Machine Messiah" to respond to many fans' fears that the new Yes would abandon longer songs; the length is 10:27, making it the longest song on the album. The lyrics are similar to Yes' usual style, even though they are by Trevor Horn; the band's regular lyricist, Jon Anderson, was not in this line-up. The song leans towards darker imagery in many parts, in large part due to a minor-keyed heavy bass guitar riff, which opens and closes the track and reappears in between as a sort of leitmotif.
The heavy metal and hard rock aspects of the song were something unusual for the band, and the song is noted among Yes fans for being one of the band's hardest rocking songs. This is due mostly to the layering of several sheets of metallic guitars, courtesy of guitarist Steve Howe. However, there is a progressive edge that runs throughout the whole song, and even without Jon Anderson's vocals, it is easily identifiable as Yes.
It is a common request in the Yes community to see the song performed live, but singer Jon Anderson refused to sing any songs from the Drama album. When Yes reconvened without Anderson in 2008, they performed "Machine Messiah" and "Tempus Fugit" with new vocalist Benoît David.
On Dream Theater's album, Octavarium, in the title track, "Machine Messiah" is referred to in a stanza that is a play on words with some of the band's influences. A cover of the track itself, recorded live at Jones Beach, NY, is included on Dream Theater's official bootleg album Uncovered 2003-2005.