Rytmihäiriö is Finnish Thrash/Hardcore/Surmacore/Death -metal band, but the band calls their music Surmacore, which is "an unique mixture of hardcore, metal and Finnish homicidal history". Rytmihäiriö was founded in 1988 in Helsinki, Finland. After split-up in 1992 and reforming in 1998 they were the first band to sign Spinefarm Records.

Current line-up consists of Unto "Une" Helo on vocals, Janne Perttilä on guitars, Antti "Ande" Kiiski on bass and Otto Luotonen on drums.

Past bandmembers: Kalle Ellilä (vocals, R.I.P. 2003), Silveri (vocals), Marko Karimo (vocals), Pate (vocals, Pate rejoined the band in '98 but left in '02), Karis (guitars), Eq (guitars), Nastis (guitars), Tuukka (guitars) and Samppa (guitars).