- 1999: Limp Bizkit featuring Serj Tankian - "Don't Go Off Wondering" (Demo) - Demo for Significant Other
- 1999: Fear Factory featuring Serj Tankian - "Cars" (Live)
- 2000: Incubus featuring Serj Tankian - Live Improvisation
- 2000/2006: (həd) p.e. featuring Serj Tankian and Morgan Lander - "Feel Good" - Broke and The Best of (həd) Planet Earth
- 2000: Metallica featuring Serj Tankian - "Mastertarium" (Live)
- 2000: Tony Iommi featuring Serj Tankian - "Patterns" - Iommi
- 2000: Snot featuring Serj Tankian - "Starlit Eyes" - Strait Up
- 2001: Dog Fashion Disco featuring Serj Tankian - "Mushroom Cult" - Anarchists of Good Taste
- 2003: Serj Tankian - "Bird of Paradise" - Bird Up!: The Charlie Parker Remix Project
- 2003: Kittens for Christian featuring Serj Tankian - "Had a Plan" - Privilege of Your Company
- 2004: Saul Williams - "Talk to Strangers" (writing credit only) - Saul Williams
- 2005: Buckethead featuring Serj Tankian - "We Are One" - Enter the Chicken and Masters of Horror Soundtrack
- 2005: Buckethead featuring Azam Ali and Serj Tankian - "Coma" - Enter the Chicken
- 2005: Buckethead featuring Shana Halligan and Serj Tankian - "Waiting Hare" - Enter the Chicken
- 2006: Buckethead featuring Shana Halligan and Serj Tankain - "Waiting Hare" (Live)
- 2005: M.I.A. - "Galang" (Serj Tankian Remix) - Galang '05
- 2006: Dredg - "Ode to the Sun" (Serj Tankian Remix) (Unreleased)
- 2006: The Notorious B.I.G. - "Who Shot Ya?" (Serj Tankian Remix) - Marc Eckō's Getting Up: Contents Under Pressure
- 2006: Deftones featuring Serj Tankian - "Mein" - Saturday Night Wrist
- 2007: Tool featuring Serj Tankian - "Sober" (Live Improvisational Version) - Big Day Out 2007 (Auckland only)
- 2007: Les Rita Mitsouko featuring Serj Tankian - "Terminal Beauty" - Variéty
- 2007: Fair to Midland featuring Serj Tankian - "Walls of Jericho" (Live Improvisational Version) - Coachella 2007
- 2007: Serj Tankian - "Bug Theme" - Bug Soundtrack
- 2007: Serj Tankian & Petra Jolly - "Innermission" - Bug Soundtrack
- 2007: Foo Fighters featuring Serj Tankian - "Holiday in Cambodia" (Live) - 2007 MTV Video Music Awards[5]
- 2007: Wyclef Jean featuring Serj Tankian - "Trouble Again" - The Carnival II: Memoirs of an Immigrant
source from wiki
