Endgame (2009 onward)

Dave Mustaine stated that a new studio had been built named "Vic's Garage" and that pre-production for a new album started in late September 2008, with Andy Sneap producing. Dave also mentioned he expected the album to be completed by September 2009, and that a new tour promoting the album was to start in March 2010, but due to difficulties with Andy Sneap's visa, the release day was pushed back. However, in February 2009, Mustaine told on The Live Line that he had finished his rhythm guitar and lead vocal parts for the new album. It will be Chris Broderick's first album with Megadeth.

Andy Sneap will also be mixing the band's forthcoming DVD titled Blood in the Water: Live in San Diego that will contain a complete concert recorded on May 20, 2008 at the Cox Arena in San Diego during Gigantour 2008 the other acts on the bill were offered a chance to be part of the DVD but declined. Megadeth embarked on the "Priest Feast" European tour with headliners Judas Priest and openers Testament in February and March 2009. One new song title for the album was named "1,320", the subject matter of which is drag racing.

Dave Mustaine was invited by Metallica to attend their Rock and Roll Hall of Fame induction; Mustaine congratulated them respectfully and stated due to winding down European tour with Judas Priest he would be unable to attend the ceremony. Megadeth and Slayer co-headlined Canadian Carnage, the first time they had performed together in more than 15 years. Opening acts for the four shows that occurred in late June were Machine Head and Suicide Silence. As of May 19, 2009, Dave Mustaine issued the following studio update at their official site: "I'm at the studio right now, Vic's Garage, and we are done! We're just right now finishing the last couple of notes on the new record, and Andy's getting ready to pack his bags and head up to Los Angeles tomorrow to get ready to fly back home on Thursday. Man, this has been a long, grueling, enduring process but it's been so worth it, and I'm so excited. I'm more excited about this record then I've been in any record since back in the 1980s. I would say, probably since, well definitely since 'Rust In Peace' there's nothing that's excited me this much - maybe 'Countdown', but this is just absolutely insane."

As of May 19, Megadeth had finished recording the album and on June 18, the album title was revealed to be Endgame. On May 26, 2009, Chris Broderick posted the following on their official website : "As for the CD, I can’t believe the way the whole thing came together. It has a unique and original sound that I don’t think could have come together with any other group of people. From Dave’s snarling vocals, to James’ huge bass sound and Shawn’s dead accurate drumming it is just relentless, and with Andy producing, it focused the sound and direction of the CD. I feel lucky to be a part of it, for one thing it definitely did, was make me expand and play in different styles. I can’t wait for the release, and I hope all of you find something in it you like." On May 27, 2009, Dave Mustaine confirmed all 12 songs are complete and they are currently mixing and mastering the record.

As mentioned by Dave Mustaine on the syndicated radio show Infowars, the name of the album "Endgame" is an homage to the Alex Jones documentary of the same name.

As of June 5, 2009, Megadeth was confirmed to headline the Big Rock Stage at this year's Japan Loud Park festival, set to take place October 17–18 at Makuhari Messe, a convention center in Japan located in the western region of Chiba Prefecture, close to Tokyo. Other bands performing at the two-day festival include Slayer, Rob Zombie, Anthrax, Arch Enemy, and Children of Bodom with Judas Priest closing the festival.

On July 7, Megadeth released their first single "Head Crusher" for download on Roadrunner Records' website. The download was available for only 24 hours, beginning at 11 AM EDT.

On August 15, Megadeth released another song, "1,320", for download on Roadrunner Records' site.

The release date for the "Endgame" album was announced on the Megadeth official website as September 15, 2009, and Metal Hammer Magazine's website were the first to review the album track by track. The entire album was put up for streaming on the 10th of September on Myspace.

Megadeth began its Endgame tour on November 14, in Grand Rapids, Michigan and ended on December 13, in Las Vegas, Nevada. The Tour featured Machine Head, Suicide Silence, Warbringer, and Arcanium.

In January 2010, Megadeth was set to embark on the "American Carnage" tour with Slayer and Testament, both giants of the thrash and heavy metal scene. The tour was scheduled to begin on January 18, but was ultimately postponed until later in the summer due to Tom Araya's back surgery.

Megadeth's "Head Crusher" is nominated for a 2010 Grammy. Megadeth has also confirmed a "Big Four Tour" (with Metallica, Slayer, and Anthrax). This will be the first time that all four thrash metal giants have played together.

Megadeth also announced a "Rust in Peace 20th Anniversary Tour", which began on March 1 as a month-long North American tour with support from Testament and Exodus. During the tour, Megadeth played Rust In Peace in its entirety and Testament played Souls of Black in its entirety.

As of February 8, 2010, and prior to the start of the "Rust in Peace 20th Anniversary Tour", original bassist David Ellefson rejoined Megadeth after 8 years. He stated in an interview for Classic Rock that Megadeth drummer Shawn Drover contacted him and had said that bassist James Lomenzo was declining and had told him that "if ever there was a time for you and Dave to talk, now is it." In an interview with Ultimate-Guitar, David Ellefson stated that Megadeth would begin writing yet another album very shortly. It was also announced that there will be a live DVD released featuring the concert at the Palladium in Hollywood, California.