Greatest Hits: Back to the Start is the second greatest hits album by Megadeth. It was released on June 28, 2005 by Capitol Records. The title "Back to the Start" is a reference to lyrics in "Rust in Peace...Polaris" from Megadeth's 1990 album Rust in Peace: "The day of final conflict/All pay the price/The third World War rapes peace/Takes life back to the start"
The selection of tracks for the album was largely determined by fans, who voted on songs in polls on the band's website. However, the inclusion of "Kill the King", a track originally released on Capitol Punishment: The Megadeth Years, was insisted upon by Mustaine. To help promote the release, a new video was made for "Kill the King."
Greatest Hits: Back to the Start reached No. 65 on the U.S. Billboard 200, selling 17,441 copies according to Nielsen SoundScan. By December 16, 2005, the album had sold about 133,000 copies in the U.S. The album was also certified gold in Canada (for 40,000 copies) in July 2011. On July 23, 2011 in Toronto, Ontario, the band was presented with gold plaques by EMI in recognition of the achievement.
Jason Birchmeier of Allmusic critiqued the album for being more of a sampler and having a more "balanced" approach to the band's Capitol Records material, rather than focusing on Megadeth's first few records.