The Four Largely Popular thrash metal bands that formed in the 1980's. These bands dominated the thrash scene.
They were,Metallica,Megadeth,Slayer and Anthrax.

runners up include-
Exodus,Death Angel,Overkill, destruction and Kreator
the big four of thrash were influenced by hardcore music and NWOBHM and went on to inspire nearly all of todays metal. Slayer Alone is said to be one of the forefathers of death metal.
by kane the main mclain July 11, 2008
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the four biggest and best thrash metal bands. metallica, megadeth, anthrax and exodus
metallica, megadeth, anthrax and exodus are the big four of thrash
by jkgvfhgk December 22, 2006
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Metallica, Megadeth, Anthrax, Exodus (not Slayer). As much as we might want it, Slayer was never considered one of the original big four (probably should have been a "big five"). I have seen Slayer replacing Exodus on several pages now including this one and Wikipedia. Not so. Slayer was often categorized differently than the mainstream 80's Thrash bands (Death metal, etc, although I don't think this exactly fits either).
The Big Four of Thrash from the 1980's were Metallica, Megadeth, Anthrax, and Exodus
by smc123 October 31, 2007
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Metallica, Exodus, Megadeth and Anthrax. Slayer is not one of the original top four, despite what you may hear. Top citation is Dave Mustaine who pushes a "top 5" that includes Slayer, but does not replace Exodus.
Metallica, Megadeth, Anthrax and Exodus are in the original Big Four of Thrash
by smc123 November 6, 2007
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